How To Troubleshoot, Service, and Repair a Motorhome or Camper Travel Trailer Rooftop RV Air Conditioner AC. FAQs

I am looking for a small roof top A/C for a small 1964 14 ft Shasta camp trailer. I currently have a 12 volt roof fan in a 14" X 14" opening. I don't need a large one. 5,000 BTU's or less. Any ideas.

I have purchased my 1st motorhome and the forward cabin ac unit will start then slow down and trip breaker.Any sugestions?thank you

hey, this is a great article. I will show my husband. He is wanting to replace the coils in our roof air in our pop up. The were smashed a little. The air works great at night but has a hard time keeping up during the heat of the day which I think is normal but he seems to think the coils being smashed has something to do with it. Let me know what u think. If you think they do need replacing, where would I get replacement coils and how much are they? thanks.

Hello, we heve a 15000 roof top ac on our 2005 5th wheel,it is freezing up. The cooling side has about one quarter inch of frost. After its turned off she starts and cools great and a few hours later freezes again. What do you think it is? Thanking you in advance.

Hi Randy,

My 5th Wheel AC/HEat just simply isn't going on. I replace the Dometic thermostat and the electrical board right under the vent inside the trailer. But still nothing. Any thoughts?

to randy godwin,how do i recharge my brisk air unit it does not have a service port,it is a 1986 model how can i add one,and what type of freon is it?

AC comes on and the fan comes on and I can hear the compresor come 0n, but it does not cool. Help Thank You

Our 2005 Damon Intruder Motor Home rear AC squeaks. Does that mean a bearing is going out, just needs oiling or does it mean the motor is going bad? Can I do some repair myself or does this require a technician?

My roof top carrier want work on cool setting but will work on fan setting it was working when I bought a week ago

It only blows regular air when on the fan setting when I put it on the cool setting the fan or compresser nothing works the air conditioner want do anything but only when I put on fan

I turned it on cool and it stayed on for minutes and cut off. It did this several times. And it was very hot in the trailer so I know it didn't hit the set temperature on the thermostat now when I set it on cool it does nothing I even push the emergency cool button on the roof and it does nothing

It's a wireless remote

I will keep checking back with you. Thanks for all your help. Thermostat was my first guess but I'm no a/c man. Again thanks for your help

Randy I figured it out. There is a little glass fuse (barrel fuse) in the ceiling. I took the fuse out for a minute and put it back in it resets the a/c it works fine now. A rv tech told me about it. I hope this will help someone because I was ready to take mine to shop to get looked at. I really like your site.

my air conditioner was working fine, and all of a sudden, it kept tripping the breaker. i would turn it back on and the breaker kept tripping, till finally it wont turn on. the heat works but all you hear is the clicking of the thermostat when you put the ac on. does anyone know what this could be

Hello, I have just about the same unit as in this article and I've done all the maintenance described. However I'm noticing lately in temperatures over 100-105 that the compressor will cycle off for 5-15 minutes every hour or so.

Can someone tell me if this is normal? Or maybe there is a service I can preform to prevent this? I'm primary concerned this may be a sign of bad things to come.

I should also mention that I replaced the thermostat last year so I doubt that has anything to do with it.

Thank you in advance for any help!

Hello Randy,

It has a knob with no numbers so I'm not sure exactly what the temp is set at but it's close to maxed out and as long as the compressor doesn't shut off then it's plenty comfortable with an extra fan moving air around.

I believe the unit is overheating as I've tried misting some water over it the past couple days during the hottest hours and the compressor has stayed on fine. But this obviously isn't a practical long term solution. I've also tested voltage into the unit and it's a clean 116V.

Thanks again!

WE have 99 Fleetwood Flair class A camper, with a 8,000 series Rooftop A/C unit. The unit stopped & we had a tech come out and he cleaned the coils and the unit. The unit was restarted using the breaker on the panel and the compressor now runs 24/7 unless we trip the breaker. He told us that it would only be a matter of time before we need another A/C unit. The units using this systems works fine. Any suggestions would be greatly appreciated.

Thanks Randy

I'll find time to run a test on the compressor.

Just out of curiosity... I've seen the overheat switch which attaches at the top of the compressor at the wiring. When this fails, does it just give out or does it maybe become more sensitive before hand?

My AC is an older 67 series and as well as it works, parts have been replaced over the years so I'm wondering if the sensor might be something worth adding to the list.

Thanks again :)

Dometic 520315.701E. Blows cold air but shuts off before the desired temperature is reached. Not connected to a wall thermostat. Runs for about two minutes then shuts off regardless of outside temp.

Thanks, Randy, for your speedy reply. Both the compressor and the fan shut off. I agree that it's probably a thermostat. Now to see if I can find where it is! Hope my husband can do this repair.

Glad to keep reading this thread. If the compressor is drawing too many amps, what's the cause? What's the fix?

I have 2000 Damon Daybreak , That I purchased 3 years ago . Everything has been working fine till today . The rooftop AC unit was working fine all week-end . On our way home today had the generator on and the AC running off from that . And the AC stopped completely . When got home , plugged it into a 110 electrical outlet , but still will not start up . Does absolutely nothing . Any suggestions ????

how do i put freon in a roof top ac on a camper??i don't find any service ports to put freon in

Hi Randy,

Its me, Daron again (still).

Re: Installing a piercing valve and re-charging with R22 Freon.

I found several types of piercing valves available online for various prices. However, do I need to have special gauges and fittings to refill Freon to proper pressure? I am having a problem finding an RV tech who is certified to refill Freon. The residential home AC techs have the equipment and access to Freon but say that they only do home units, not RVs.

Can this be done with a simple refill hose kit from an auto parts store? Do I need to purge the old Freon with a vacuum pump before I refill?

Daron

hey randy: I have a RV with dual DUO THERM A/C units. I was plugged in to 3o amp, and made mistake of trying to turn on rear A/C also. It would not come on. I tried later to use the generator, and still nothing. No fan, and no compressor. Front A/C works good. The rear A/C worked great last time it was used. I got on roof and pulled cover. everything looks connected. The motor spun freely, also the blower wheel. Could the start or run capacitors have gone bad?? I'm not sure which is which. There is one on the left front, and one on right front next to looks like a relay. Any help I'd appreciate.. Chris

hey randy, I also forgot, I reset the breaker and checked the wiring plugs. They were all tight. Chris

hey randy, thanks for the reply. My a/c's have the dials on the a/c unit. How do I check the thermostat with voltmeter?? I want to replace both a/c's, but at $650-700 each, lotta money. They are 26 years old.

hi randy: I checked it today. I used a compressor to clean everything out, a little maintenance. I checked for AC voltage at the breaker, with the generator on, it shows 124volts. so, it's getting power. Wife told me it turned on once, and I haven't got it started since. I checked the two plugs, and they are tight. So to get at the back of thermostat, I need to remove the small cover from the thing?? Then, am I checking for battery voltage or AC voltage?? which terminals do I check?? Do wires have to be removed first?? Thank You, Chris

thanks for the response randy. I have a good meter, Ill check it out tomorrow . thanks for your help, chris

hey randy, well I checked it out today. I checked the power wires that go to thermostat, I got like 19Volts. So, meter shows 124Volts at the breaker, and around 19, where the hot wires go to the thermostat. Does this mean the thermostat is bad?? I didn't see any loose connections. This is with genny running. I tried ground in different spots, same issue.

Chris

Thanks randy, i appreciate it.. Chris

I have a Dometic Duo Therm 57915.622 AC Unit. It works well for almost 15 years old. The trouble is that after it shuts off from reaching the temp setting, it tries to start again in only 20-30 seconds and trips the circuit breaker. If I turn it off manually and let it rest for about a minute it starts easily. I've already replaced the capacitor to no avail. Is this a problem with the thermostat or the control box?

Hey Randy, I have a Duo Therm AC unit on my fifth wheel(2006) . It doesn't run at all, the remote works, there is 120v going into the main circuit board and 12v,no power on the fan wires into the fan relay,(low/high speeds). In between there is a "selector box " for cooling or heat modes that attaches into to the main board by a telephone cable( a single electronic card, no way to test it). Box is located in the wall. Not lights are "coming on" on either modes when selected. There is power into the unit(120v) , no noise, no hummin, all fuses ok

Your comments are appreciated..tks cs

Thank You for your prompt response, there is no manual control or thermostat on the wall,besides the "Selector Box" for cooling or heating. The remote allows for temp setting, fan speed and other parameters. I will look for it again, just bought the fifth wheel. I found very little information regarding the ac in the manuals. Hoping you can help..carlos

Today I went outside to check my coachmen rv and heard a humming sound coming from within before I opened the door. When I got inside it had stopped, so I waited to see if it would sound again. It did. My a/c would hum about 5 seconds and cutoff. I went to the wall mounded thermostat to make sure it was off...and it was! I turned on the heater and it worked fine BUT every 3 minutes the a/c would try to come on too. What in the world could it be??

Randy, I have solved my ac problem. I eliminated all the fancy circuit boards and remote control; by replacing it with a basic wall thermostat, using a 120V /24v transformer (similar to the ones used in a doorbell) for the low control voltage, a sequencer (relay) (similar to those used in straight cool split residential ac systems) turns on/off the compressor and the fan. I also installed a 5 amp fuse to protect the transformer in series in the 24v control circuit. The power(120v), is supplied via connection block. The thermostat senses the temp sending a 24v signal to the sequencer relay using the yellow wire (green could be used instead off yellow)turning the ac on/off as required. So far so good..... Regards. cs0155

Can the roof AC cover be left on the exterior AC unit when traveling? I want to keep dirt and insects from impacting the coil and unit exterior. Can it be left on when traveling?

Randy, Thank goodness I found you. We put in a Coleman motor to replace the Fasco motor. The noise is deafening and the vibration is bad enough to shake the camper. It seems to be wired correctly. What's next? Summer is on it's way in Lower Alabama. Thanks in advance.

Could the weight of bolts throw off the balance? If the fan blade clamp screw is not centered on the flat spot of the shaft, would that throw it off?You must pardon my ignorance on this subject but trying to get this resolved. Again, many thanks.

Dude, you are the best. I narrowed it down to a faulty fan blade. Whoop, whoop. You are an r/v genius. Thank you.

Have a 2008 5th wheel camper with the following AC problem. The unit/fan will not run when you turn it on. It will run after you spin the fan with your hand and run fine, then when it has to kick on by itself again the fan will not turn. Where should I start to trouble shoot this problem? Thanks. Sorry but I hate to pay dealer tech prices if I can do it my self.

Thanks Randy, I will try and take a look at that this weekend and get the part ordered before spring break time. I will let you know if that fixed the problem. Love this information site.

Hey Randy, got the numbers off the AC unit on Sunday and took pictures of them. Now looking on EBay for the correct parts I need. My unit is a CSC model # 833508564 serial # 060712278. I had 2 capacitor's on my unit. One is a 2 prong ( short oval) and one is a 3 prong (round). Which one is the run start capacitor. Or just change both while doing it. I am guessing a RV parts store has them or can order them but would probably be higher than on eBay . Thanks for you help Doug

Hey Randy, sorry it took me a few days to get back with you. Got the parts ( it was the short oval capacitor with 2 wires , fan capacitor )took the old one off , put the new one on ( plug and play ) turned the AC on and it started running . Thanks for all your information, it saved me a RV repair Tech cost. This is a very helpful site. Also buys your parts off the internet, much cheaper than RV store. Thanks again for your help. Doug in Georgia

Hey Randy, I have an older model coleman 13,500 btu unit. It comes on and runs for about 5 minutes then the fan cuts off and I can hear the compressor still running. If I just leave it on the breaker will flip in about a minute. You can cut it off for about 15 minutes and do it all over again. I checked up top and it seamed that the fan motor was getting really hot so I replaced it and the fan capacitor and it still does the same thing. What else could be causing this?

Randy, I am having the exact same problem that James is referring to on my Coleman Mach series unit. Any ideas on what could be causing this would be greatly appreciated. I guess I'm glad I haven't replaced the fan motor yet. But it's getting hot in Texas! Thanks in advance!

I have a 2000 coachmen rv with 2 duo therm roof units. I started the generator to operate the ac everything ran fine, and decided to convert the power over to 110, but now the ac and fan will not run. I have checked the breakers fuses and capacitors. My thermostat shows 12 volts at the furnace but not at the fan or ac. What would you suggest for me to check next?

where is the transfer switch located for a 2000 coachmen rv? How can I check the switch to verify that if its good?

I have a 1992 Monaco crown royale with twin duo therm roof a/c units ( separate thermostats ) I ran the a/c on the gen a couple of weeks ago with no issues. I tried to run it over the weekend on the gen and now it will not work on gen or on the land line. The thermostats won't light up. I have voltage at 120v circuit breakers (separate per unit). I removed the cover on the rear roof top unit and I have no power. I am not sure if one unit powers the other ? I haven't looked at the front unit yet. Looking for any ideas

Thanks,

Randy,

yes you are correct neither will operate. It seem crazy that both would fail at the same time ? Do you know where I could find a wiring schematic on this system? It almost would seem that both problems would have to be connected somewhere. Are thermostats a common failure ? I have a 91 Jayco with the exact same one and have never had any issues. Thanks for the prompt response.

Both power sources have the same problem. The land line and the gen.

How could I test the transfer switch ?

Thanks,

That's not a problem, but what am I looking for and how does the transfer switch work ?

Thanks,

Randy ,

I spent about 3 hrs tonight looking at the issue I have. I have power at both roof top units, I can jump the power and get all fan speeds and the compressor to kick on but I still have no power at thermostats. I even removed my thermostat from my jayco and swapped them out and it made no difference. I am leaning toward the circuit boards on the rooftop units. Just thrown how both units could fail at the same time. Thinking possible power surge from gen or shoreline? Are these common for failures that you are aware of?

Thanks,

FYI I did replace the board with one from my jayco and it eliminated the problem

all works fine , just can't find a board replacement

Thanks,

Hi. We have a 2012 Lacrosse and the AC quit. An error code of E1 is showing on the thermostat. We have had the AC checked and the person said the AC unit is fine. We have replaced the thermostat and checked the breakers. All this and no fix. I know the error code means loss of communication between the thermostat and the AC unit. We are at a loss on what is wrong. Please help!

Hi' hope u can help me I have 2014 wildwood rv trailer and for some reason my ac is blowing hot air can you tell me what I need to do please . Greatly appreciated . Thanks

RV Roof top AC not even trying to turn on. Thermostat works for the separate Propane furnace. Thermostat also has a switch for "fan only/ hi/low" BUT... I did not check if the fan works ala this switch on the Thermostat. (83 miles away right now). If the fan works via that switch, then does that mean that power is also also getting to the AC mode in general? Then, could it be a relay? Circuit breaker is OK (on). Is there some sort of lock out? DuoTherm. Thank you thank you thank you.....

Hi have a dometic 2600 the light on the unit inside the van is not lighting up and the unit is not responding to remote control the fan is working ok and the compresser works for a few minutes then cuts out I can't turn matchine off has button on unit is not working and has I said it's not responding to remote control ?

Hi we have a roof top ac. The fan would come on but no cold air. We bought a new ac and we are still having the same problem. What could be the problem?

Yes, it is a wall mounted thermostat.

i have a travel trailer and ehe I turn the ac on manuall, it will bog down, cool for 30 sec or so and then kick off blowing cold air and it appears the fsn kiks on. the fan setting work just fine. any suggestions?

Hi, we have a coachmen rv freedom express 2012 and it didn't come with a manual for the ac. My son was turning the unit on and off and now it runs in an energy save mode when on cool. Meaning, the fan shuts off in between when the compressor is not running. It used to blow air all the time even when he compressor wasn't running, which is the setting we need. Any ideas? Thanks.

HiRandy, the continuous fan setting doesn't cool, just blows air. I'm looking for the cool air to run continuously while cooling with compressor on and also in between when temperature is reached but compressor is off.

Hi Randy,

Just purchased a 2012 Keystone Raptor 4014LEV Toy hauler about 2 months back. The I have two roof mounted a/c's and a portable a/c in the garage in the back. I have tried cleaning the coils on the back of the unit and that helped some, but last night when I got home (we are full time rv'ers) the a/c wasn't blowing cool air at all. At 10 PM last night the temperature on the thermostat was reading 75 degrees with all 3 a/c units running. The portable unit in the garage area is an 8,000 BTU, the main unit in the Living Room/Kitchen area is a ducted Coleman Mach 15,000 BTU, and the A/C in the bedroom area is a 13,500 BTU. The A/C in the garage blows ice cold and the 13,500 BTU blows ice cold. What do you think this problem could be? As well the filter is clean on the unit that is giving me trouble, but I have read a little bit in here about the evaporator coils possibly needing to be cleaned? Can you get the coil cleaner at like Lowe's? I should also mention that when you open the vents on the main unit to let air drop directly down it blows hard, but is still not cold; and when you close them to use the ducts you can feel very little air blowing throughout the ducted vents. Even the vent that is very close to the main unit is barely getting any air and it seems that the unit is bogging down a bit. Have been fighting this issue in the Texas heat this summer, and trying to get the temperature down from 85-90 degrees inside the trailer down during the heat of the day. Any help that you may be able to provide is greatly appreciated. Thank you SO much and I'm sure my fiancé and son will thank you too!

Hi Randy, the three options on the temp control pad are 'fan' 'cool' and 'heat". Yes the ac unit ran the fan continuously in the past when set to cool. When temp was reached you could hear the compressor shut off but the fan still blew, and then when the temp rose again you could hear the compressor kick in, but always there was air blowing. My son was cycling the unit through the three options the other day (he is three) and now it stops blowing in between cooling. On another note, we also have to always shut off the fuse to the air to run the heat otherwise the air continues to blow in addition to the heat. But that has always been since we bought the camper (haven't had a chance to fix that yet bc we don't have the manual).

Randy,

I cleaned the evaporator and condenser coils last night, and put some more of the reflective insulation in the massive windows that are on that trailer. As I was going through and installing the insulation in various windows I thought about the big skylight in the bathroom. I took it down and put a piece of the reflective bubble wrap insulation. A flash of light caught the corner of my eye, and I think I have found what my problem may be with the air flow. On each of the ducted vents the manufacturer, Keystone, only put reflective tape between the duct and the vents, and the vents are leaking air into the roof between the paneling and the rubber roof. Talk about cool when I pulled that skylight down. So as you can imagine I felt like a dummy. I'm going to try to cut this story short. I have air escaping into the "attic space" on my fifth wheel. Do you know of something that could better insulate/connect the ducts to the holes in the roof where the vents are? Thanks so much, and as an update, it was a brisk 68 degrees in there this morning when I got up; but still not very much air flow through the ducted vents. Thanks again for any info you may be able to provide.

Randy, I have a 1992 coleman popup, the other day i tried turning on the rooftop a/c, and it sounded like the compressor was havinghaving problems starting, it was shaking and sounded like it was chugging. The fan worked fine and didn't vibrate or anything. A couple days later it seemed to turn on fine. Last weekend the fan runs, but it sounds like the compressor will not turn on, and will not cool. But like I said, I'm not sure the compressor might be on, but I dont think so. Plshelp! Thank you

Rob

Thank you randy. I will give it a try.

Hi randy. I have a 2005 coachman trailer. I took it out for are first weekend camping and the air works great but after 3 to 4 hours it freezes up? One thing I noticed was there is no " click" sound on the thermostat when setting the temp. Also the compresser never seems to shut off? Any thoughts?

Wall mounted. I also forgot to mention that it will not shut off now? Just keeps running? I have to use the breaker to turn it off.

Thx Randy I will give it a try. Can I use a normal house thermostat ? Or does it have to be a RV pacific thermostat?

Ok thx Randy. I will let you know how I made out.

Well I got the new thermostat in but as soon as I turned the breaker back on the air came on. Even thou it was in the off position. So next step is a new control board I guess? Is that something I can do or is that a dealer project ?

Well thx again for all your help Randy. I will try a new board and let you know how I made out!

Trevor. Ontario , Canada

Hi Randy, I have been experiencing similar problem where compressor keeps running, and I have to use the breaker to shut it down. Where is the control board located? on the roof? or inside? It is a Duotherm/Dometic.

Thanks

OK sir,I have a 95 winning dual air. Conditiioners was driving with both air's on started to smell wire burning so I couldn't stop for a little when I did could not find anything we are in Phx with dogs. Anyway my wife set the airs at 70 which I've learned in the past not very good for the generater . well then all of a sudden the front unit smokes the board what would cause this ,the high voltage side of the board is all that burnt any suggestions would be appreciated .

I have an Airxcel RV roof unit (mod 8333D876) with a compressor that will not shut off, freezing us out overnight. I just replaced the thermostat, but still no cutoff. Various sites around the web seem to point to the relay, but according to the manufacturer's diagrams I have a "PTCR Device" instead. Should this be my next attempt?

Hi Randy. It's Trevor again with the 2005 coachmen. To make a long story short I got the new control board however they have discontinued my board and gave me a newer board. The original pt# was 3107541.009. New up dated one is 3313379.000. On the new board there is one plug missing the original had . However it does have one other type of plug on it my original does not have on it? I am at a bit of lose as what to do now? Any ideas?

Ok thx Randy

hi all, i have a 1995 coleman 7330-720 roof a/c and it seems the compressor is on all the time. when i turn off the unit i can hear the compressor still running and have to turn off the breaker for it to stop. i removed the inside cover and removed the compressor relay yellow wire and it stops the compressor. does it sound like the relay needs to be replaced. when i get the part i know i need to turn off the circuit breaker but to i need to watch out for the capacitor wires or will i get a shock removing the wires. they are larger purple wires and i think its a capacitor but dont know if i could get a jolt from them.

I have a Duo Therm rooftop AC on my 99 Holiday Rambler. A few things are happening:

1. The front unit will make a clicking noise in the control box even when the thermostat is off.

2. The unit will start when using the generator, but more often than not the front unit tends to kick the breaker after start up.

I don't know if these two things are related, but I would like your opinion. It seems as if I could be looking at a capacitor going bad???

I have a 1997 22' Fleetwood Class C with one Coleman rooftop A/C that is still cooling OK, but at times, will not cycle off, leaving us very cold inside. I replaced the thermostat, but nothing changed. It works and cycles OK about half of the time. Is it just the really hot weather I am experiencing while going through the desert SW ?

I have a 98 Coachman Roof top A/C that the fan will run, but there is a low hum and the lights will dim in the camper for about 2 seconds and then the hum kicks off and fan keeps running. It will keep "trying" to kick on but will never get the compressor running to cool. The thermostat is on the unit itself.

Would hot weather have an effect on A/C on a class c motor home rooftop unit. My problem is the a/c will run for a time, then it trip the breaker. And that is with the genrator or 30 amp goundline.

hello randy my ac unit in my camper trailer was tripping the breaker every now and then but now when you put the thermostat on cool it just makes a clicking sound in the ceiling

We just bought a Coachman cadet and the air condition runs for about 3 min. and then shuts off. The filters are clean. the coolent refilled. Not sure what is wrong.

Randy, our a/c unit in our rv has suddenly started vibrating making it really loud and annoying. my husband went on top the roof to investigate and discovered that the rubber washers in the motor mounts were worn and broken. He replace them with metal washers and broke a bracket in the process. What can we do to fix this hiccup?

its a 2012 dometic duo therm

The AC on my RV only runs on fan mode. When it is turned on to just fan, the fan spins and it blows air. When I switch it to AC, or cool mode, the ac just makes a humming noise and no air blows out. Fan works on all settings, high and low. AC just makes the humming noise on all the settings, high and low, and no air blows out at all. Thank you!

I have 1986 jayco rooftop ac runs for about an hour then fan quits running an ihear a humming .I shut it off for five min and it works for awile then dose the same thing

Hi

We have a 2014 Cedar Creek and the air conditioner is dripping around the output in the bathroom. What can we do?

Hey randy, I really appreciate the advice you gave me a couple of days ago. We replaced the capacitor (it was bad) and the AC ran for a couple of minutes then it stopped again. The fan still works, the air does not blow when AC is turned to cool. Do you have any other suggestions?

Randy, we got it working! Thank you so much for the advice. You have saved us hundreds of dollars!

Hello Randy! MY boyfriend and i just bought a trailer and are living in it year round. We live in the valley where it is quite hot and depend on our ac. The other day i took off the cover to clean the filter that recirculates the air through the trailer because one of our three ducts was not blowing out cold air very hard. The other three ducts were blowing out cold air strong but the one close to the unit itself was very weak. After cleaning the filter i restored it and now none of the ducts are blowing out cold air. I dont know if this is because there is a leak or because i caused a problem after cleaning the filter. When we take the filter off and turn it on, all the ducts blow air again but very lightly, any ideas as too what the issue is? Thanks!!

What would cause my a/c unit to kick on and off consistently after reaching the desired temperature and eventually causing it to trip the breaker?

My ac keeps bogging down every few mind and smells very hot like electrical hot. It is also not blowing very cold air like usual. I went on the roof fan spinning fine and it appears to be clean. Me and my babies are HOT any ideas could it be low on freon maybe. The fan mode works just fine also

Thank u so much for answering my question:-) is the capacitor something we can locate and check ourselves or should I leave it to a proffesional?

Thanks Randy for taking my question....I bought the camper used

it's a 2005 so I would say it's the same age.

we have a Coleman roof AC on our Fleetwood. It just started leaking inside the RV, not from around the perimeter of the unit but from inside of it. We can't find trouble shooting info or schematics. Where are the weep holes ? We figured that would be the first place to start in the process of elimination. Thanks !

I have a 1986 popup with Coleman roof ac with heat cool good but when compaser shout off it get warm inside before it comes on where it use to run all the time an when you turn control knob off fan still runs you have to unplug to turn completely off an as sone as you plug it in the fan runs.

John, In my Colman 733B887 ducted AC unit I replaced the existing electronic board with the new modification. I have 115v power to unit but can not find/get any low voltage to T-stat! where is it? i see no transformer nor can I pull up any DC Voltage. I was successful once only getting fan to run I think by using 12v power from heater stat wire. Help

jim

Randy, I have a duro therm a/c. Just bought the camper. I have read all of the post and you are a good person. Lots of help.

My problem is I know nothing about electricity nor camper a/c. A/c will not start. The fan runs when I turn it to fan. But a/c won't kick on. Like I said the fan runs when turned to fan but when turn to auto, nothing. When I move the temp setting up or down there is no clicking or noises. Where do I start?

Randy it is a wall mount. I have another camper that when I move the air setting up and down I hear a click. With this one nothing.

Can I get the thermostat checked or just go buy a new one.

I have a 1991 Alumalite I purchased about 4 years ago & been living in year round here in Florida. The rooftop unit is a Duo-Therm BriskAir. Within the past 3 days I turned the A/C on due to higher temps. I had to turn the thermostat 1 notch from the lowest setting to hear the compressor come on, Last night around bedtime I noticed there was no air coming from the vent. I pulled the filter & saw the coils were frozen up. After reading the posts above, I see I can try to clean the coils. Should this be done front the bottom (or inside the camper as well as from the rooftop with the cover removed? Also, if there are connections for recharging, are the connections a different size indicating what type of refrigerant to use?

I might add I do not have a means of transporting this 5th wheel. When I purchased, I made arrangements to have delivered to my property where we are building a permanent residence

Randy ,

My A/C is a DUOTHERM DOMETIC , When it turns on it cool fine , after a few minutes , it seems like a short power surge , you can hear the difference , goes down, goes back full force! i went up top removed cover fan turns fine by hand, coills look pretty clean. Any ideas ?

Thanks , Pam

Hi, I have a dometic roof ac.

When ot reaches set

Temp the unit shuts off but then continues to come on and go off again. I was thinking thermostat but according to earlier post it could be low on freon?? How can i tell ??

Ok. Thanks a bunch !!

Randy, my thermostat does not work on my 2002 Holiday rambler Motorhome. I bought new one and it won't power up either. Checked the 3 amp fuse at the control box. Any thoughts?

Hi randy I got a duo therm roof top ac unit. And I just recently took the motor apart and freed it up from being frozen. Now the fan and everything works good and when switch to ac the compressor I can hear kick on and blows really cold then come back little later and is just blowing about the temp of the fan air? Ideas?

My wife has a trailer with a Coleman roof top AC. How do you get access to the blower wheel to see if the fins are clean? Does the motor and blower wheel get removed from the top outside of the unit as an assembly? I don't see how to access the fan otherwise. I am concerned the blades have built up with dust and debris and want to inspect or clean it, to make sure it is pushing the air properly.

Hi, Randy. Great site. We have a 2015 Jayfight 32BHDS that we got in December. It has two Coleman Mach rooftop units (15K BTU main ducted unit with wall-mount thermostat and a 13.5K BTU unit in front bedroom with controls in shroud at ceiling integrated with unit). We've camped several times using AC with no problems. Last weekend I was running only the main 15K unit and it ran most of the afternoon and night. The next morning no air was coming out of ducts. Upon inspection I found that my evaporator coil had iced up. We shut it down and just ran the 13.5K front unit Sat and Sunday. Both evap and condenser coils are pristine (as you would expect on new trailer). Could this just be normal reaction to user (me) error? We had thermostat set pretty low (65-70) and nighttime temps outaude got down into the 60s. Fan was on Auto and unit ran pretty much constantly. From all I've read online since we got back it sounds like I should have had thermostat set higher (ex. 78) and had fan set to "On" (instead of Auto) and "High". Appreciate any advice.

Randy, I wanted to add that it appears my freeze control sensor had become disconnected from the evap coil. When I removed my filter cover and shroud from ceiling, a white wire was hanging down. Several veteran RVers on RV tech forums have said it is the sensor and they are notorious for coming loose. Wanted to pass that along in case it helps someone. Thanks again!

Hi Randy, I have a 2015 salem Hemisphere 300BH with a dometic thermostat that is showing the E1 error. The problem I have is that the A/C will not cut out. The only way to cut out the A/C is to turn off the breaker. Then I can not get the fan or furnace to come on.

Any idea's?

Hello,

I have a 2001 Prowler with 13.5 Coleman Mach.

Live in it Mon-Fri for work. Worked fine on Friday but when I got back on Monday... It worked fine for about 5 minutes then I could hear a change in tone(louder hum) for about 20seconds then would blow warm air. After about 15 minutes it will start blowing cold air(68degrees with laser temp) again for about 5 minutes then louder Hum again start blowing warm air. interior Controls on unit not ducted. Any thoughts?

Update:

The Campground owners took a look at it. Coil that can be seen from inside RV was embarrassingly dirty(dog,smoke, cooking oil, clay like substance) and was causing the compressor to overheat and shut down on our first truly hot day yesterday. They cleaned it with a solution until it looked new and straightened out my fins. Works great now and seems to be much more efficient. It must have been working harder then it should have for awhile. Thanks

I have a Sprinter camper with a roof top a/c. I used it a month ago with a 5000 watt generator and the a/c worked great. I put the camper up till now. Now I'm setting it up in my back yard, where I have a 30amp hook up and the a/ c want do anything. I have a wall mounted thermostats and nothing comes on. No fan, furnace or a/c. Not even a noise. This happened last year also and a RV shop couldn't find anything wrong. In fact it started right up for them. But not for me. Help!!!

Hey Randy,

Came across your sight doing a search. We have a 1998 Thor Fifth Ave. First rig we have bought. Previous owner didn't use it much last year (only 4 times) and said the AC went out at the end of the year. The unit has a wall mounted thermostat and roof top AC. It runs the furnace fine and blows hot air. Also the fan works in that mode. Any clue on what I should be checking out this weekend for diagnosing? I was going to take the cover off and check it out. Im assuming its a bad compressor or low on Freon.

Hey Randy,

When you turn on the AC on the thermostat, the fan starts up and you would think the cold air would start blowing out. Sort of sounds like its going to kick on. Im not on site yet but will be tomorrow. So not sure if there are 2 capacitors as you mentioned. With the fan starting up could it be a possible second capacitor (if there is one) or possibly freon low? Just debating if Im going to need to replace this whole unit or not.

Appreciate all your help!

Hi Randy,

I have a 2001 Monaco Dynasty with twin Duotherm Penguin A/C units. A few days ago we were running the units and noticed an unusual sound of flowing water coming from one of them that lasted a couple of seconds. A few hours later we noticed water starting to drip onto the floor from the return intake and one of the output vents. This had never happened before. I took the shroud off of the unit and the drain tray was empty. The tray drains to and outlet hose under the RV. I haven't been able to determine exactly what happened although I have suspicion the drain pan may have cracked. Do you have any insight what might have happened and how to determine if the pan is cracked? It doesn't appear to be very easy to access the pan.

Thank You, ... Christopher

Hi Randy, thank you very much for your thoughts. I'll give a coil cleaning a try and let you know how it goes.

Christopher

Hello, I have a 2012 forest river sunseeker with a dometec a/c . I am getting an E5 error code which is causing the a/c to turn on for a few seconds and then shut off. When I tried running the a/c with my generator the a/c functioned properly. Any suggestions?

I just bought a 94 30' kit camper with a ducted roof top ac, when I attempt to turn on the ac, I can hear the compressor start but no fan, when I turn it to fan instead of auto and flip it to high fan I hear a clicking noise coming from a relay or something up top in ac. What I've done so far: I've taken the shroud off spun the fan seems to spin free easily, had someone turn ac on and tried to spin fan to manually start it, no luck, replaced the larger capacitor that has the 3 different areas, only change was it tripped the power strip I had the camper plugged into, I put the original back on, now doing the same as origanly stated, I thought the smaller capacitor was for the compressor but not sure. Could it be the relay? The guy I bought it from said he was told it was the motor by a mobile mech and was quoted 400 to replace it, after the things I discovered I don't take his word for anything he's just not very bright when it comes to these things or plays like he's not, and I can get a new unit for 500 with shipping so I thought 400 was way steep for a fan motor. I have a feeling it's something simple possibly fan but it spins free so I'm hesitant to just start replacing it. Any help appreciated!

I have a carrier Air V air conditioner in a 2007 travel trailer with a remote control. The unit will shut off when in air conditioner mode. The heater and fan will both work butt when switched to cool it will shut off.

Two weeks ago the compressor would at least run for about 20 seconds but now shuts off immediately. The emergency cool button won't do anything either.

I got a 2001 terry camper. When i turn my ac on it blows cool air but its weak and also the fins are coming off the outside coil. What do you recommend

Hi Randy, First of all, this site is AWESOME. I have a 1985 Chevy Shasta. 4,500 original miles on the replaced engine and 42K on the RV. I have a leak in the A/C unit. Water comes inside. I removed both covers above, completely cleaned EVERYTHING, oiled where needed, removed a terrible caulk job around the a/c basket it sits in and professionally reapplied sealant. Inside, I tightened the bolts that came through the inside control shroud and cleaned as well. Up above, I noticed inside the styrofoam cover, a "channel" if you will, with a little water stain. It looked like this is where the condensation water should be allowed to travel out of either end when needed. I blew both of these out as well. After doing all this, the air was definitely colder, but alas, I still have a leak. RV is parked level. PLEASE Randy, any advise. Thanks and God Bless, Dave

Hi Randy I have a 2000 Dolphin with dual ducted roof air. Changed settings and both units quit working. Check breakers reset them still nothing. Is there a fuse that .ay cause this?

Changed zone setting then turned stat off now air will not restart.

It is a function of the thermostat. Zone 1 is front unit zone 2 is rear. Also realized that water was leaking on the rear furnace under the bathroom sink could this have anything to do with this issue. Thanks

Hello Randy, captaindb00 again from 2 days ago. Still getting leaks inside as it's getting REALLY hotter here in NV! After doing hrs. of research, I found out there were possibly 1 of 3 a/c units used for my RV, but nobody can tell me what 1 of 3 they may be. I want to replace the gasket but don't know what to ask for. I am also going to raise the "basket" or "tray", (whatever it's called), that the unit sits on. The nearby RV dealer said there should be a 1/4" to no more than 3/8" gap between this tray and the metal on the roof allowing the water to travel away from the unit. I have NO gap at all, Thus the need to raise it, install a gasket and seal it. Two questions please. Any ideas on who to contact to see which gasket I could match up to in order to find one? Lastly, where does the water exit out of the unit and go onto the roof? I would like to see if this area could possibly be plugged. Thanks again Randy and God Bless.

The furnace does share the same thermostat. So, if the water leak did short out the thermostat, wouldn't the lights on the thermostat be non-functional. Because the thermostat control still looks like it always did. Lights up when buttons depressed, etc.

If it is the thermostat shorted out, how would I fix that? What would need drying or replacing?

If the thermostat lighting up is an indication that it is not shorted, what else might cause both ac units to suddenly cease at the same time?

Haven't done so yet, but that is my plan for tonight. It is the 5 BUTTON 3109228.001 COMFORT CONTROL CENTER SYSTEM and the two roof ac units are the Duo-Therm by Dometic. My wife found an operation manual for the thermostat online, as well as a detailed trouble shooting guide. If I get this figured out, I'll let you know, and if you have any other ideas, please feel free to share. Your willingness and helpfulness are greatly appreciated.

I have a 1980s pull along camper I had out two weeks ago and the ac worked just fine. Now today I went to turn it on and there was nothing.. Checked breaker and it wasn't tripped. Do you know what the problem could be? Thanks Brandon

Got it working!! No voltage was going to the ac from the breaker..Got a new breaker

Hi randy,

I am in the process of replacing my fan motor on an older 1994 duo therm roof top ac, I have the old motor out, the motor cam with new squirl cage and fan blade however this duo therm isn't friendly when it comes to getting the old squirl cage out and new one in and I really prefer to replace it and not use the old one. What I've tried so far, I got the foam cover off with minimal damage.. Took a smal chunk out of the to think area but that's it... Any suggestions on a patch appreciated if you think it needed, behind that foam is a cover that has the mounting bolts on it first I thought it's peranatly attached then I noticed it appears like it may have been removed so I gently started to try and tap it off and one side started coming off ok but as I got to the top it wasn't wanting to go anymore and I wasn't going to force it so a taped it back in place, little nervous that I would screw it up and the motor won't mount straight but I will make sure it's back in place and metal tape it well around the seems. Next thing I did was remove 3 bolts inside the camper the mounting plate I couldn't get the fourth bolt out it's just spining hopfully it tightens back up. But I was able to see the opening isn't large em ought to get it out from inside. Now I assume I'm looking at loosening the coil that makes me nervous as I don't want to damage it or the lines. What is your suggestion or the proper procedure to remove this squir cage? Also a question on the bolts I remove inside I assume they are the mounting bolts and my plan is to re instal and tighten them down good before I go back up too and jar anything around as they were the last thing I did. My question is how tight should I thighen them and how do I go about tightening the 4th bolt that would come all the way out? I hope it tightens up fine won't know till tomorrow. By the way is the condensation suppose to drain out on the roof or is there supposed to be a drain line somewhere? When I had it working last week it was just draining on the roof.

Thanks in advance sorry for the long post.

I have a 2009 Zinger with Coleman Airconditioner. The fan blows properly at all settings however the air will not cool. I cannot hear the condenser even try to turn on. I have wall mounted thermostat. I am thinking capacitor?

Great site by the way :)

Jamie

original post two weeks ago. Thought I would let you and your readers know that the compressor is bad. No replacement parts available for the Carrier unit, replacing the entire unit. Did Carrier get out of the RV air conditioner business?

Thanks Randy. I felt a lot more assured making a two hour drive with only one part with me. New capasitor worked and cold air blows again!

Hi Randy. First, let me apologize ahead of time for my poor terminology and wording as I'm not experienced with this type of thing. We have a '93 terry pull camper. I'm not sure of the make of the AC but it's ducted and has a wall mount thermostat. The AC worked fine last summer with no problems but the first time we turned it on this summer it wouldn't blow cold. The fan came on and worked fine as it did blow air...just not cold. I didn't hear the noise I used to hear right before the cold air kicks in. (would that be the compressor kicking in?) A couple weeks later we tried to use it again and nothing happened at all, not even the fan. While trying to figure out what was wrong I realized the breaker where the camper is plugged in to electricity had tripped, so I flipped it back on and everything worked fine including the air being cold! So I was thinking everything was fixed...until the next time we went out and turned it on and just the fan would run again...no cold air. Any ideas as to what the problem may be? I can use a meter to detect the voltage of things if I have specific instructions as far as the settings, which wires to test, and what it should read. I also should mention that we have not done any cleaning of the AC accept the inside filter since we have owned it (11 years) because I wasn't aware that we needed to. That will be taken care of while trying to fix this problem. :o) Thanks for any help you can offer.

Hi Randy, i have 2006 travel trailer. Recently my ac unit has developed a squealing noise when it kicks in. Fan is working fine, just when it kicks in and reaches temp and shuts off it has a squeling noise. Couple people said i need to oil the shaft??

Thanks for your reply! You said in your article ...

"Check the required voltage and model numbers on the new AC capacito when ordering a new one. "

Will this information be on the old capacitor or is it in the AC manual somewhere? Also, does it have to be the exact model number that's in there now, is there a certain brand I should be looking for, and can I use the turbine oil my husband has to oil the motor? Just trying to make sure I understand everything before I drive to where the RV is and get started. :o) Thanks

Anissa

We have a 2008 Motorhome with a 2 ton Coleman A/C Model 6537-871 that is freezing up, checked the coils they look good, it has no piercing valves to add freon so what now?

My problem is my A/C works fine until the outside temp gets over about 92 degrees. When it gets hot the compressor won't stay on and even kicks the breaker off sometimes. The compressor gets too hot to touch. Did not have this problem last year. What would cause the compressor to overheat?

Have a57915.622 brisk air in my sundowner horse trailer. Worked fine last season, this year the compressor wont kick in. The fan works fine. I changed out both the capacitor and hard start capacitor. Can you give me a clue as to what I need to look at next?

Randy, my roof air is on a 2007 Damara we bought used with very low miles. The wall mount thermostat is not the original. The a/c seems to work ok on low speed, will work for awhile on high (no mid speed because its not the right thermostat) will eventually pop the breaker. As long as the tv, microwave and fridge are off, it will run on low but turn one on and the breaker pops. I ran it all ok, everything on, in my driveway on 20 amp...but every camp site, 30 or 20, the breakers pop. Any suggestions? Any idea of brand model thermostat I should have? (07 Safari Damara 293ts)

I don't know if it's been cleaned before, we bought it used a year ago and we haven't had it cleaned. Now even low speed pops the breaker and it will not start again. Do you have any idea what the original thermostat make and model should have been? We are currently on the road, so we'll probably have to fix this when we get home in a few days.

Thanks Randy. Heading home for a look see. The replacement thermostat has 8 wires, the motorhome has 7 so whomever installed it left off the mid speed wire so everything else would work.

Randy... i have a 1983 prowler travel trailer with a coleman roof mount a/c. My question is how to find a replacement fan motor for it? I have searched the Model # however it says RMR is no longer in service and it doesnt give any replacement #'s.

Thanks

Randy, I have a 1988 Coachman Classic motorhome. It has a Coleman tsr mach 3 roof unit on it. The fan motor will come on but cuts off after running for 3 to 5 minutes. If I turn it to cool before it cuts off the compressor comes on and cools fine. So the fan cuts off if I have it turned to fan or if I have it turned to cool. It's does not trip any breakers. After a period of time it will cut back on on its on and run for 3 to 5 minutes and cut off again and so on. I replaced the run capacitor and no change. Any suggestions as to what the problem may be?

Thank you for the quick response. I held my hand on the motor till it kicked off and waited for it to come back on. It did get pretty hot. It got got enough that I didn't want to leave my hand on it. It didn't get as hot as I would figure a bad motor would get. That still could be the problem though. How can I check the motor other than just by it getting hot? I hate to buy another motor and it not be the problem and not be able to return it.

Hi Randy! I think we've solved our problem! I got up there to get the capacitor out and realize there were 3 of them. I took out the one that I thought looked most like the ones I'd seen while researching this problem (the black one). While I was there, I noticed that a black wire that goes from the compressor to the square relay box (I think that's what it's called) had a broken disconnect....one crimped end was broken in half and so it was not making good contact. I went ahead and took the capacitor in to have it tested since I already had it out and the guy said it was the correct one and it tested good. We replaced the broken disconnect and the AC worked fine after that. We haven't been out to use it since then but I'm hoping that was the problem and it'll continue to work fine the rest of the summer. Thank you so much for all of your help! It's greatly appreciated!

Anissa

Hi Randy, I have a 2000 windsport rv, it has 2 air conditions, the rear works just fine, the front doesn't work at all, I hear a click noice when trying to turn it on but it won't start up at all, any suggestions would be appreciated thanks.

Thanks for quick respond, how do I test capacitors, looks like this one has 3 of them, sorry I never done this before.

Helo Randy my ac made a loud pop sound the ac is on the top of rv it is a 2010 Jayco on the in side it smells like electric wire had burned.did not find any, found that the capacity had blow the top off. Is that all in need to do is replace it?

Opinion please. I have an old (circa 1988) 6799-714 Coleman A/C that cools fine. Non-ducted and thermostat self contained.

It was dripping inside and the tech went up and cleaned some drain holes out a couple of weeks ago. No water. The sound of the unit changed and continued to change. Last night the motor slowed down and stopped.

Now the fan will not spin up any mode. When I turn the unit, on all it will do is hum (even in fan only mode). I can turn the blower wheel by hand, but it is not "free spinning" and when I turn the unit on it seems to "seize up" the wheel. Hasn't blown a circuit breaker. We are in TX so the unit has been on almost 24/7 for the last two months.

I'm physically not able to get on the roof myself, but knowledge is power. I'm leaning towards a bad blower motor?

???

Thanks,

Bill

Helo Randy thanks for your help went and pick up a capacitor this morning. They told me that it was a run capacitor put new one on working grate.

Thanks

Craig

My unit is running backwards what I mean is the outside coil is cooling the inside is heating what to do

Hi Randy

My Coleman RV air conditioner runs and cools great. My concern is when the compressor kicks on I hear a rather loud 'thunk' which has the habit of waking me up at night. I'm assuming the compressor is torquing in its mount at startup and making this thunk sound. It also thunks when it shuts off but not as bad. The fan motor runs quiet without any issue. This is strictly the compressor. Any idea? Thanks in advance.

Thanks. I'll find new parts and let you know how it works out. Thanks for the quick reply.

I just bought a 1995 Gulf Stream conquest I turned the ac on and it ran fine for a few hours in auto mode and then it kicked out and you could hear it clicking at the thermostat but it would not come on and then after a few times it would kick the breaker out. Any suggestions.

Helping a friend work on his motorhomes ac's. He has three, the front unit is working the two rear are not. He had an unknown surging problem with the motorhome not the campground. Units were working fine prior. He bypassed the surge protector which was not help. Since the surge happen several times with a few minutes in-between them and the units having time delays, could it be the capacitors? Thanks for any suggestions Kevin

Hello , this thread is great, but I haven't seen my exact problem, can you give me some advice? On my 2002 R-vision (by trail lite) my rooftop A/C is a Duotherm and the 3 speed fan isn't functioning properly, the speeds all seem to slower than they use to and not pushing enough air volume. I'm guessing capacitor(s) and or motor (maybe dry bearings?) Any advice you can offer would be great

Hi Randy, thanks for the quick response! I'll look into it and let you know how it goes.

Hi again Randy, I oiled the one side of the motor, at the sleeve, I turned on the unit and it hummed, squirrel cage didn't spin, I manually started it spinning, it worked properly on L, M and H for a few seconds, then it slowed down and didn't move as much air. So firstly, I'll replace the start capacitor (when I took it out, it seemed to be covered in a clear, oily sticky substance). Since it ran for a bit but then slowed down do you think I should replace other capacitor as well? (is the other larger capacitor a run capacitor?) Thanks again

I came here to figure out how to fix my compressor issue and all it says is it is usually better to replace it... I know it doesn't need to be refilled with refrigerant because if they leak at all they leak all the way to nothing.... kinda obvious. So someone here know anything about them because this forum didn't help me at all. My problem is that the compressor starts up, but draws a lot of power from other devices, possibly bad capacitor, but they are pretty new. After running properly for a while it starts to only run a few seconds at a time and then bogs down and shakes a bit and dies.

Old rooftop duo therm quick 12 a/c with a starting capacitor, run capacitor, and relay all hooked up to compressor. The capacitors have runners connecting them together and the other end of each goes to a different terminal on the the relay, while the thermostat wire and black power to compressor are on another terminal. The thermostat wire provides 120v as well as week as whatever the capacitors put out to run and start. Thx for any tips

Hello again Randy, I'm just back to update you (and others) on my repair. Long storey short...both capacitors were bad, motor was fine. The smaller capacitor had leaked oil, the larger silver capacitor had blown out the back side. $50 in parts and back in business, thanks for your help!

When i came home today my ac was only working half power what just happend??? It was working fine all week its way less noisey too... but still blows cold air... im clueless

I have a duo therm model 59516.531 can I wire the fan up directly to 110 or is it dc

i have a new dometic 13,500 a/c unit . it will run for about 1 1/2 hrs the it will stop and the compressor will not start again. what going on with it

let ask you this i got 2 new 2000w yamaha gen tie toghter is this enought to run that a/c it 13,500 and pull 14.8 amps

i wont touch that a/c due to the warranty

How do I clean the drian hole on my roof top a/c? Do you have to take it up or can it be done from the inside?

Great Article. Clear and concise instruction that even I could follow! DON

Randy, this is a good no, nonsense article. Thanks for it.

I'm having some problems with my Carrier ducted unit. I have good flow out of the rear vents but the front vents aren't getting any pressure. When I feel up inside the intake I can feel cold air in that vent. It really seems like there is leaking between the blower vent/fan and the intake. I've sealed all of the possible seams in the lower unit. This feels like its above the lower unit. Is there a way to service this area of the unit? Looks like the whole thing is a big plastic cowl on the top portion held on by a few screws and clips, is this where I should look?

--Jonathan

Hi Jon, there may be some air leakage or perhaps the duct is collapsed or blocked in some manner. Often overhead ducts are very narrow in thickness and this allows a minor blockage to divert the airflow through the other vents. This seems to be a common problem in ducted systems. You may access the ducts through the vents or by removing the upper unit if you have to. Any way to check into the ductwork will do to check for obstructions.

Randy

Hello Randy , I have a duo therm from 1995 , when it is first turned on it blows cold and semi swift but as time progresses it seems the wind speed slows way down to barley any air flow ..... I've read on other post about cleaning coils , have not attempted in shroud removal as of yet ....thanks for any suggestions , sincerely Lyle

Hi Lyle, This problem sounds more like a fan capacitor than dirty coils. The fan has a capacitor which starts it up and which keeps it running at normal speed. Or you may have one that runs both compressor and fan. These are relatively inexpensive and easy to replace. I'd recommend replacing the capacitors first but the coils still may need cleaning. Ask for more help if needed.

Randy

We've had our fifth wheel for a few years and it would randomly squeak now and then. Well starting yesterday when it kicks on it squeaks but not a high pitched squeeking. Then it stops and runs completely normal. Its a 2005 keystone laredo. We took the plate out on the inside when we got it so the air blew directly into the living room. We decided to put it back in and see if it cooled better a few days ago now these noises are happening.

Hi Ashley, more than likely the fan motor bearings are getting worn. You may try lubricating them and this may help for awhile, but it may be only a matter of time before the fan motor needs replacing.

Randy

I have a 2013 Heritage Glen 5th wheel and my roof AC unit is blowing ambient air. I hear the compressor kick in, but the temperature doesn't change. It is a dometic 1500w AC unit. I have already changed out the thermostat, but no change. I have visually looked at the unit and it does not look dirty or clogged.

Hello DarylG--Are you sure the Freon in the unit is fully charged? If the compressor is working and the fan is blowing properly, the Freon may have leaked out. Anything else you can tell me about the unit?

Randy

Thanks for answering, I suspected as much. I don't know how to check if there is freon in the unit. I have been told this is a sealed unit and adding freon is impossible. Is that true? Does this mean the unit is trash?

we have a 2013 voltage with 3 a/c 2 work but the 3 one trips a breaker can you help

Well we didn't get it greased in time. Its started squeaking and making a thumping noise today. Then about 5 minutes ago it started making noise so I stood by it and it slowly slowed down until it completely stopped and blew no air or made any noise. When I switch it to on instead of auto it runs hot about a minute then slows down until it turns off again. Still think its the motor?

Good evening. I have a 1998 Dutch Star with two ducted AC units. The one in the back is fine, the one in the front stopped blowing The compressor runs; I got on the roof and looked - the fan was not spinning. I gave is a "push start", and it started to run, but by the time I got down into the rig, it wasn't blowing. I'm thinking start capacitor first, then motor. Can you help? Thank you!

Hi Randy. I have a 1998 Road Ranger 5th wheel. We recently had a new converter installed. Now my air conditioner/furnace won't come on. I'm thinking it's the thermostat. The thermostat clicks but the air conditioner doesn't do anything-- no sound like it's trying to come on-- simply nothing. Am I right in my assessment and if so, do you know of any articles that could help my husband change it out and whatever circuit board the dealer said we'd have to change if we replace the thermostat. Thanks for your help.

Hi Randy,

My Dometic Duo-Therm Brisk Air unit has stopped working, even blowing. I can hear a clicking sound when it should turn on, but nothing happens. Any thoughts on what I might test and/or try? Thanks.

Aaron

I'm planning on replacing my old duo-therm 13.5k ducted that I'm starting to have a lot of problems with. Its about 15 years old

I was looking at replacing it with a new 15k unit. Do I just need a new upper unit. Descriptions don't say if they come with the control circuit board .

Hi Randy, Thanks for your help in advance.

I have a new rv with a Coleman Mach 8 9000 btu a/c rooftop model. Hooked up to 30amp service. I have run the unit a couple times in temps high 70s and low 80s. Fan starts and runs and compressor kicks in. But with the thermostat turned up completely the compressor runs abour 4 minutes and then shuts off for 5 to 6 minutes. This happen however warm is is inside. Is this a normal cycle for this kind of unit? I also put a wattmetter on a plug and see about 110volts with compressor on, 113 to 115 when its off. A laser temp guage shows temperature at output vents are 18 to 20 degree colder than what is going in. Seems like it should run longer to get inside temps lower in the initial startup. Unit is under warranty but I am in remote Alaska location for the summer with no access to dealer or service shop unit fall. My experience with older a/c units is they do not run compressor just 4 minutes regardless of conditions. Thanks. Jimbo

Thanks Randy,

I will check the compressor temp and see if I can figure how to bypass the thermostat. Good ideas. Am I correct in thinking the 4 minutes on and 5 to 7 minures off is a little short when first starting it up?

Hey there...WONDERFUL thread here!

Just installed a Dometic Brisk Air 2 in my Skyline Weekender 247. Installed very easily, power, control plug, manual inner control unit, everything. Powered back up and turn the fan on, but the compressor won't kick on. The only variable I have is I didn't install the supply/return divider due to lack of tools.

Could this be causing the compressor NOT to come on, or do I have another issue?

Hi Randy,

I have a different problem than most. I have a 2005 Bounder 37U with two AC units. The rear unit works fine. The front unit will blow cold air when needed, but will not produce heart when the controls are set to use the AC unit as a heat pump. We often camp in the spring and fall and up in northern NH & Maine the nights get cold so the AC units are typically used for heat if the outside air is over 45 - 50 degrees. This unit worked properly last season, but in the spring it will only blow cold air when we have set the thermostat and control panel to AC heat. Again, using the same settings on the rear unit works correctly. Any ides as to what to look for?

I .ve been having a problem with my ac and furnace it seems like a relay or the wall mounted thermostat the air wont shut off when it gets to temp and sometimes the furnace blower will run and not shut off untill I kill the power ? then today my wife went to turn on ac and it would try to run then kick out then in then she smelled it getting hot and shut it off any thoughts ?

I have an older model Coleman mach and the fan blows just fine but when the compressor tries to kick on it boggs a little then clicks and the fan keeps running a couple days ago it was working just fine till the power cord came unplugged now that's all it will do what could be the problem

Randy did I do something wrong that you haven't responded ?

Thanks Randy how hard is it to replace the thermostat its a duo-therm wall mount ? Kirk

Thanks Randy I will let you know how it turns out

I sealed around base of my AC unit now when it rains water builds up and drips on the inside of trailer, should I remove the sealant. Does this prevent rain from draining?

Randy,

Have a 2014 Coleman Mach 13.5 A/C only (no heat) unit as 2nd air in trailer. Probably have used this unit less than 15 times. Just discovered it is not blowing cold. Blowing hot air only.

Have tested both capacitors and they are strong and good. Verified thermostat is working fine. Inspected coils and evaporator, they are clean (look new).

When on top of trailer, it seems like the fan motor to the compressor is not working, but the compressor is warm to the touch.

Being such a "new" unit, would think the compressor would not be the issue.

Any input would be appreciated and thank you in advance for your response.

No, compressor is not running.

Is this a sealed unit? Can Freon be checked or added to??

Thank you for the input and pointing me in a direction that hopefully is the right one!!

Just an update on the a/c... Had to have a tech come out to determine issue. Ended up being circuit board control box. $100 part & $200 service call. Guess still cheaper than a new unit, but you'd think as expensive as these things are they would last more than 2 years!

Not happy, but cooler now

Hello Randy, I have a 99 dometic dual ducted ac system. Rear unit works fine, front air runs up to 3 minutes then throws E5 code on thermostat. Compressor cycles then throws code again. Do you know what this means? Thank you.

When I turn my Coleman Mach on fan it works great,but when I put it on cool the compressor hums but fan goes off

Thanks Randy,

Although the coils in both units were surprisingly clean, prompting me to get up there and look did something right. The wiring was a jumbled mess in front. I rearranged everything, replaced the covers and its worked ever since. I did remove all mud dobber nests, blew out a few leaves. Thanks for the suggestion.

With the fan on manual it just hums and will not come on this is on a road trek van

Hey Randy, My ac unit leaks water inside my rv when it shuts off. But not always. 2014 Hill Country,I just use the one roof top unit because it vents to the bedrm via ceiling ducts. Last summer was first use and almost immediately noticed a brownish small stain from corner of unit go down the side of rv. any thoughts? Thanks pal

Hi Randy,

I have a 2003 Fleetwood Prowler with roof mounted ac. Couple of weeks ago the fan moter wouldn't start (it would hum and was hard to turn by hand) so I replaced it and the capacitor. Worked great for a few weeks but now nothing seems to work on either the ac or heater.

Can't get the fan to start and the compressor never kicks on. I have checked the breaker and it's good. Also checked the fuses and they are all good.

I checked the fuse on the thermostat and it was good. I had a newer thermostat I was going to install anyway so I replaced the thermostat, still didn't fix the problem.

Any ideas?

Thanks Randy. I found the manufacturers repair manual online and following their flowchart I tested the voltage between the red and Y, B, GH and GL at the thermostat and I only read 10.5 volts instead of 12.

Also, if I have any lights on, the readings at the thermostat drops down to less than 10v.

I also tested the 9 Pin connector in the ceiling that plugs into the control board and I should have 115v between Term 1 & 3, 5 &9, and 6 & 9. However I'm getting very low ac readings there - like 20v.

I tested a couple of outlets just to be safe and got 120 at the outlets.

Thanks again for the help so far.

Thought I might add this just in case it matters. My Battery is not hooked up to the camper at moment. I'm just plugged into a 30amp connection. The battery hasn't been hooked up in years, but I've never had a problem.

Hi Randy,

Have read all the threads and found one that sounded like our problem (Larry about 3 yrs ago and closer to the top) but he never wrote back to tell if he got a fix. Here is our problem: 1993 Fleetwood southwind, we are 2nd owners for last 18 years. Coleman duo top mount AC units. Never had a problem with either unit, mostly run only front unit. Arizona heat most of year. At Lake Powell in July, hooked up to park power, ran front unit all day as had to leave one older dog in RV while out on lake. Ran fine. 9pm AC quit. Checked back unit, it also would not come on. Checked every breaker. REset button on generator and tried to start each one with generator, had selector switch set on rear or front as we checked each unit. No wall thermostat, only on ceiling unit. Fans would not even come on. Then went back to campground power with same result. All other appliances and lights worked. Just took OHM meter out to check connections of circuit breaker and tested all outlets and gfis. It is like no power is getting to the units. Checked coils and inside shrouds for dirt, pest damage found none. Suggestions?

Frequently when we start up our A/C or just the roof A/C fan alone a dry white powdery dust comes out initially. Any causes or fixes?

Camper Dave, I cannot think of anything in the AC which would cause this powder. You'll need to remove the shroud and take a look-see to find out the source of the powder. Sorry I cannot help you out.

Randy

Hey, My Coleman ducted 15k unit started squeaking, then stopped running all together. I ordered a new motor and replaced it. The fan now runs, but NO COOLING. It was cooling fine before the motor gave out. Any ideas? Its an 06 Raptor with just one unit, wall thermostat.

I removed all three capacitors-one is for the fan,the other has what i guess is a hard start thing. i don't have a capacitance meter, but, when i attempted discharge, no sparks on any of the three. when i ran resistance check with a Greenlee DM-20 set at 2000k, it started out counting up then stopped at one on all three capacitors

Hi Randy, I have a rooftop Dometic AC and the front AC clicks but wont turn on. Any suggestions for me?

Have a 2014 Winnebago Travato with Coleman AC w/Heatstrip. When I turn on AC runs/cools for few minutes then compressor shuts off. Then no cool air & compressor does not kick back on. In fact it almost feels like it is blowing hot air.

heater comes on when I turn on ac what causes this? turned it on to check it out and heard a click then ac came on and then heater came on also disconnected wires for heat at thermostat and it still ran

Hello I have a 2005 35 ft holiday rambler and yesterday I had the AC going and all a sudden lost all power. It turned out to be the breaker coming from the outside power source and reset it came inside and no AC. All I hear is a click. And also my gfi isn't resetting. Are both of those powered together cause they say they are on different breakers. Anybhelp would be awesome.

Thanks randy, where can I find these parts locally??? Or is my best bet online? Thanks for the response sir.

My penguin heat pump unit blower quits for 3 minutes then restarts. Sounds like the thermal limit in the blower motor is cutting power out. Compressor is unaffected. It still did this with all ducts open on top of the unit. I checked the dual run capacitor and it is at spec. The run cap field wiring shows resistance. What else can I check?

Randy, I tried the operation with the the thermostat in blower "auto" and manual low and high. It did not sound like there is a mid speed change when that is selected. The motor was spinning freely but it was running real hot. That is why I thought the problem would be the "run" capacitor. There is no issue with the compressor, I believe. The cap does have an internal cutoff of some sort. Not sure if that could be the problem. Not sure how to test that. I have a new blower motor and capacitor coming. I'll try the blower first since the cap is a week out.

Randy, sorry I'm not very technical so this could be a stupid question, the rooftop AC was working fine, then we drove for 2 days through an intense rain storm. A couple of days later I tried to turn on the AC and got nothing. Dead. I tested the fuses and they appear to be OK. The breakers are set to "ON". Could the rain have caused this?

Hello Randy,

Having a problem with my Duo Therm Brisk Air 57915.531 AC unit. (No heat and air ducts right from the unit) Turned the switch on and the compressor ran fine but no fan. Fan ran ok if given a nudge so replaced the start cap but still have no fan at initial start up; although the fan motor spins freely and will still run if given a nudge.

Also, this is a three speed motor and selector switch but it's only operating on low speed, no matter what position the switch is in so hardly any air movement in the TT.

Do you think this could be a fan motor or control board problem? (Air is plenty cold coming out of the ducts)

Thanks in advance...

Hey Randy,

When I said "no heat" I meant that this unit does not have an element for the optional heat mode, and I have not upgraded it to do that. Sorry for the misleading statement!!

The AC / Fan switch is located on the ceiling assbly. That said, even in just fan mode, the speed does not change from low - med - high. My suspect is the fan motor - and now I noticed some vibration that I failed to mention. The motor shaft movement is fine for up and down, but does have some play when moving it in and out.

I have no real life experience at this stuff, but am thinking the motor may have had a winding go south and that's why the new start cap didn't help at all.

I'd appreciate your thoughts on this - I know without "being here" it's pretty much of a guesstimate, but you certainly have more experience at this than I do!! : )

Thanks Randy - appreciate all the help and advice and will let you know.

Mike

Hi Randy

I have a Damon UltraSport with a Carrier V ac unit. The problem I'm having is. The unit will run fine without no problems while still, on gen or plugged in. But when I try to run the unit while traveling the unit after about 10 to15 min. Trips the 20 amp breaker.

I have trying tighten all the wires,I also ran a seperate wire from the breaker to the unit with same out come. I also changed the breaker. I even changed the capitator. Do you have any other solutions. to this problem?

my onboard generator Genrac 7.5 Kw diesel.

Hello Randy,

Thought I'd post the results of my AC dilemma!!

I changed the hard start cap earlier, since oil was leaking out of the top. Of course that cap is for the compressor and has nothing to do with the original evaporator fan problem.

That said, I went ahead and changed the run cap and the fan motor would start, but would still only run on one speed - so new fan motor installed and I'm back in business.

Kinda strange to me that all three would have issues at the same time, but that seems to be the way it goes for me with about anything!!

Thanks for the suggestions - much appreciated!

Mike

Hello Randy I have a 06 motorhome with 3 Duo Therm conditioners. Recently the front one will start blowing cold air for about 5 mins then start blowing warm air. Is this a sign of low freon or compressor going bad

It sounds like the compressor is still running but not positive. I have not taken cover on roof off yet. I have not left air on to see if it goes back to cooling or not, hate to put that much warm air in house. We are in south Texas and weather has been warm.

Purchased Atwood Air Command Ducted 13,500 BTU A C Roof Air Unit for a Montana fifth wheel. The one we purchased is run by thermostat and the one that was damaged was run by remote. Is there any way to bypass the thermostat because we do not have a thermostat on this fifth wheel. Mexico, Mo

We have just now discovered that when we make a right hand turn our camper leaks water on the passenger side, not just a few drips either. It is a 2005 Tioga camper. We want to find an inexpensive way to fix it if possible. Or looking for a place in wa state that won't too much.

Elaine, try the products listed in this roof repair article.

https://axleaddict.com/rvs/RV-and-Camper-Trailer-R...

We have a 94 Shasta 35ft that has been sitting for several yrs. The rooftop a/c control knobs won't turn like they are frozen. Any suggestions on how to get them moving again. The previous owners said it had been serviced about 4 yrs ago and everything was working at that time.

Thanks Randy! I bought some on the way home tonight.

I need a condensor for a brisk air 15000 btu ac. Phone numbers please

On a camper with a roof mount AC and a gas furnace , If you remove the furnace it has a plug with two blue wire and a red and yellow wire. What do you have to do or rewire so AC works?

Have ac unit that's acting like it has no power coming to the thermostat. Changed out both capacitors and switched out thermostats.

Do you have any suggestions?

My rear RV a/c plus heat pump blows hot air after 3 minutes soon as the unit turns

the 3-way switch only works on high speed not low or medium.it is a brisk air unit.

We have a Coleman Mach on our Jayco 5th wheel that is 12 years old. It has just quit cooling. Runs but did not cool. Can you tell me what to check.

I have a 1986 class c t.v. and am having trouble with rooftop a.c.. when turned on it blows air but when compressor kicks on the lights go dim and it kicks off. Any suggestions?

I have a problem of my main cabin AC not getting as cool as it did, and now the breaker on the generator trips after a few minutes when I turn on both of my AC units. Any suggestions?

I have 2000 Coleman rooftop with wall mount. Nothing works. Av or furnace. You stated in other comments that it's probably a capacitor. Could you explain how that is. Thanks in advance.

I have a 2015 Jayco with rooftop air The air only blows on high and it is cold. The low does nothing or I have clicked it over from high to low and it would just hum on low. Any ideas?

How would you check to see if it's a capacitor problem or fan motor? It will hum on low. It's two speed. Coleman Mach on wall thermostat

I have a Coleman Mack 48000 series Model#48254C969 3 weeks ago we had a close lightning strike and the AC stopped working I checked all the breakers they were fine I changed the thermostat then the unit runs but doesn't cool or get cold at all I changed both capacitors and the unit runs fine just doesn't cool off at all any suggestions as to what direction I should be looking at next it's been out for 3 weeks I'm in South Louisiana and it's a lil hot here although I used to only run it at night to sleep and the unit is only 3 years old any suggestions would be deeply appreciated I've been reading and researching everything I can get my hands on

Randy,

After removing the A/C shroud, I found the rear coils reasonably clear of dust and debris. However, the tubes coming from the compressor were coated in 1/4" of ice, and the forward coils were a solid sheet preventing any airflow. Is this a compressor failure, and am I looking at replacing the entire A/C unit.

Thanks,

Steve

sfoulger61@gmail.com

I have a 3 yr old Jayco Class C. Air cond blows room temp air. No refrig. Any ideas?

Randy,

After removing all of the ice very carefully, I found the airflow was 100% better than before. I also determined that leaving the A/C on during the day did not give the unit enough time to thaw out any build up that had accumulated during the day. Now I leave the unit off while I'm at work and cool the RV off when I return. I don't seem to be accumulating any ice, and airflow is at its best.

We bought a 2017 palomino Columbus 2 weeks ago

The front a/c yesterday started having a constante clicking noise that seems to get worse as it goes

Any ideas were already frustrated

Thanks and love your articlesp

The battery for my camper was shocked up backwards and now actually kicks the breaker. What damage could it have done?

Converter is fine, ac has power, will run all day on just fan but kicks breaker once its on cool for few minutes, even makes a little cool air once in awhile. Someone said maybe contacts was sticking

Hey, I appreciate the thorough article! My AC fan stopped spinning, and makes a quiet hum or buzz when I power it on. My understanding is that the issue could be with the motor, capacitor, or a relay. I'm decent with a multimeter, but am not sure what I'm looking for. Can you please help direct me on what I'd be looking for to diagnose the problem?

Having problem with A/C fan not wanting to come on when you turn it on from inside. If you climb on camper roof and spin fan with hand it starts running. Question is what could be the problem . Replaced new fan motor and new starter and relay capasitor.

I have a 2004 Fleetwood Discovery motorhome thermostat is stuck on Zone 1 gas heat and won't do anything any ideals

Need your opinion please.....replaced Dometic a/c with Dometic, compressor stopped working. Was wondering if a Coleman could be used as a replacement.

Have 2006 country coach with two roof air by Coleman. Both have access and heat pump. Thermostat runs both circuits​ including propane Furness. ALL worked fine 3 months on way home used heat pump in front unit worked fine first night 2nd night propane backup came on. Got home rear unit works fine front unit does nothing no noise nothing. Spun fan reset thermostat still nothing.

dometic 15000 btu w/heat pump. when zone 2 and temp are selected unit tries to come on. overload protector trips then reset and unit tries again to come on, overload trips. this just keeps repeating. fan blows, no cool air. overload protector already changed

no i have not. i will and let you know. thanks Randy

I'm having a problem with condensation, I know enough to be dangerous so any help would be appreciated! Right now my solution is a bucket..

hello just placed a new brisk air on my fifth wheel and the thermostat is reading E1 help im in las vegas and its summer lol tried to reset nothing what can i do ???

I have a 2014 Shasta Flyte.

Before it was Dripping Condensed Water from the roof when the Air Conditioning was Working and from Not Long ago there is Not Any Condensation. It's Completely DRY Around the unit !?

I opened the Cover and the Coils are as Clean as Could be, as well Everything around.

I located on the Sides 2 Openings, which Appears to be the "Dripping Points" for the Condensed Water. They are Completely Clean and DRY !?

At the Same time the Air Conditioning "Turns OFF Less Often" just to Keep the 90 F, and when Set on 80 F, or Lower, does NOT Stop at All !?

Yes, I'm in Arizona, and the Temperature is 109 F Outside, but it Seems that the Air Conditioning does Not Work Properly !?

WHAT Could be the Problem ?

What Should I do ?

I will Greatly Appreciate Your Competent Opinion !

Do the control knobs just pull right off of of the roof top A/C units? I want to clean the air filters on a Coleman Super Mach (1970s)

and the inside cover has 2 screws to take cover off but in order to take it all the off the control knobs will need to be taken off. I just don't want to start pulling on the knobs and break something

Put new a.c. fan motor on Colman mach will only run on low speed. Turned thermostat on high speed but no change in speed what do you think

Hi, my rooftop AC unit stopped cooling, the fan motors turn on but start off very slow but the compressor never comes on , I tested the compressor directly and from the relay with a hot wire and it kicks on and cools so idk why it won’t kick on itself , I thought capacitor but then I don’t remember what it was but I changed my mind on capacitor, anyway can you help? Thank you sir!