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

Updated on September 14, 2017
Randy Godwin profile image

Randy is a lifelong lover of the outdoors and especially camping. This article is intended to help the RVer save money and time on repairs.

A new Coleman 13,500 BTU A/C unit ready to install.
A new Coleman 13,500 BTU A/C unit ready to install. | Source

The Importance of RV AC Maintenance

The rooftop air conditioners used on motorhomes are made to give many years of dependable cooling efficiency. But in order for the AC to operate dependably each season, it is necessary to keep the rooftop AC unit on your motorhome clean and properly maintained.

Occasionally the motorhome rooftop AC needs repairing and this article will assist you in knowing which parts of your RV AC to replace or service.These repair and maintenance tips are very simple to follow, even for those with less than good hands-on experience.

If you are unfamiliar with how a motorhome air conditioning system works, this article will help you understand which parts of the motorhome rooftop air conditioner unit to check, service, and repair.

Condenser and Evaporator Coil Maintenance

Roof air conditioning units are the same as ones used on other types of RV campers such as travel trailers and pop-up campers. Your motorhome AC system may have one or two units to help keep the camper cold, or warm if the RV AC units have optional heat elements. These repair and maintenance procedures are identical for all types of the aforementioned campers.

After a few seasons of use, it isn’t unusual for the AC unit(s) to not cool the motorhome as quickly or as efficiently as it once did. Even though you have kept the filters clean on a regular basis, the evaporator and condenser coils will eventually become coated with dirt and grime which inhibits airflow and cooling efficiency.

Before attempting any maintenance or repairs on the rooftop AC unit be sure to switch off the electrical supply to the unit, either by tripping the breaker or by unplugging the motorhome from the electrical receptacle. You are now ready to remove the RV AC shroud by unscrewing the four bolts securing it to the RV AC unit itself.

Accessing the AC coils

Removing the RV AC Shroud retaining bolts
Removing the RV AC Shroud retaining bolts

How To Clean The RV AC Coils

This coil is badly in need of cleaning
This coil is badly in need of cleaning

After removing the AC shroud you will be able to see the evaporator and condenser coils on either end of the RV AC unit.

If they appear similar to those in the photos above then they need a thorough cleaning to allow unrestricted airflow through them.

A good wet/dry Shop Vac will help to keep you from making a big mess during the cleaning regimen.

Although regular household cleaners may clean the coils to a certain extent, AC coil cleaners made especially for the purpose, like the ZEP product below, will remove the grime build-up much more efficiently and will not harm the coils themselves.

Follow the instructions carefully for the best results and use the Shop-Vac to remove any excess cleaner or grime from the RV AC unit. Use a coil fin comb to straighten any bent fins because they too will keep the airflow from moving through the AC coils efficiently.

These fin combs are very inexpensive and may be used many times in the future on both RV and home AC coil fins.

Cleaning Your RV AC Coils

A/C Coil Fin Comb

Air Conditioner Fin Comb
Air Conditioner Fin Comb

Straighten out those bent coil fins and increase the efficiency of your A/C unit.

 

While the RV AC shroud is removed, it is a good time to service the fan motor and clean the fans themselves. Whether your RV AC unit is made by Coleman, Carrier, Duotherm, or Dometic, it will have one fan motor which turns both the squirrel cage fan and the heat exhausting fan.

This motor should be oiled at this time.

If your RV AC fan motor has regular bearings in it there will be oiling ports at each end of the motor. It may be necessary to remove the top metal sheeting from over the fan motor to access the bearing oiling ports.

A few sheet metal screws will have to be removed to allow you access to the bearing ports add oil to the bearings.

If no oil ports are evident, then your rooftop AC unit has sleeves instead of bearings. You may still oil the shaft at the point where the sleeves are contained in the fan motor housing. The oil will seep inside and help the fan motor last much longer.

A fan motor with sleeves cannot be rebuilt economically, as can the bearing models, and must be replaced with a new one. Check the ads below to find the right fan motor for your RV AC.

Maintaining the AC Fan Motor

RV AC fan motor with a sleeved bearing.
RV AC fan motor with a sleeved bearing.

How To Replace A Motorhome AC Fan Motor

If your AC fan motor is slow to start even after oiling, or needs a nudge to get it going, it will need rebuilding or replacement with a new one.


As stated previously, a bearing model fan motor may be rebuilt fairly cheaply and will last for many more years. But not so a sleeved bearing AC fan motor.

If your unit seems to be in pretty good shape a new AC fan motor may be ordered to fit your particular RV AC unit.

Check out the links on this page to find the type of fan motor you need to replace your model Click on the ads to look further on the Amazon site if you do not see your model of fan motor. There are many sizes and models to choose from.

Replacement of the AC fan motor is a simple job with only a few tools required for the project. Mark the wire colors before removing the fan motor if the connection isn’t a simple plug-in type electrical connection.

Test the new RV AC fan motor before replacing the AC shroud to check for proper alignment and fan clearance.

Replacement RV Rooftop AC

Removing and Replacing the Fan Motor

RV AC fan motor with retaining screws removed from AC chassis.  Your RV AC model may be different.
RV AC fan motor with retaining screws removed from AC chassis. Your RV AC model may be different.

RV AC Capacitor Replacement

If the fan or compressor fails to start and the AC unit merely hums or trips a breaker, it is possible the starting capacitor is malfunctioning. The capacitor stores electricity to give both the fan motor and the compressor an extra boost when the RV AC unit first starts. It is not unusual for this item to go bad.

The capacitor is easily replaced in the event it has gone bad. Note the wiring before removing the old AC capacitor and install the new capacitor in the same manner. Your AC unit should now start and run fine. Check the required voltage and model numbers on the new AC capacitor when ordering a new one.

A capacitor.  Often a cylindrical container, but yours may differ.
A capacitor. Often a cylindrical container, but yours may differ. | Source
Model and serial numbers on RV AC fan motor
Model and serial numbers on RV AC fan motor

RV AC Compressor Problems

Compressor
Compressor

If, after determining the switches, capacitor, and relays are not at fault, the RV AC compressor fails to operate correctly it is usually better to just junk the unit and buy a new one.

Unless you have access to a used compressor and have the means to replace it and recharge the system yourself, it will be too expensive to repair in most cases. Under normal circumstances the compressor will last much longer than the warranty covers.

The thermostat and switches may be purchased online by finding the correct model and serial numbers before ordering the new parts. These items w\are very easily replaced in most cases. Pay attention to the wiring connections as always when replacing these electrical components.


Protect Your Motorhome AC Unit In The Off Season

Your motorhome AC unit should give you many seasons of dependable operation if serviced annually. The use of a cover for the RV AC unit is highly recommended during the times when the motorhome is not in use.

These inexpensive RV AC covers protect the unit from being exposed to moisture, extreme cold or hot temperatures, and debris from storms, birds and insects. They will more than pay for their cost over time.

If your RV AC unit needs replacing, please see my article on how to install a new rooftop RV AC unit. Replacing your old unit with a more efficient RV AC unit is a very simple and quick procedure you can do yourself. Don’t be afraid to try these service tips yourself. You will learn much about these wonderful RV air conditioners.

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    • Randy Godwin profile image
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      Randy Godwin 2 weeks ago from Southern Georgia

      Hey Russell, more than likely its a bad capacitor. Any local AC or electric motor repair service can test them for you. A relatively inexpensive and easy fix.

      Randy

    • Randy Godwin profile image
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      Randy Godwin 2 weeks ago from Southern Georgia

      PrarieFire, if the compressor is coming on then the AC should work unless the Freon is low. The residue on the tubing could be a sign of a slow leak.

      Randy

    • profile image

      Russell T57 2 weeks ago

      Hi Randy

      I have a Coleman Mach ducted ac and today it stopped cooling.

      The fan runs but the compressor does not try to come on at all. It is cool to the touch. The fan runs on high and low if T-stat is on cool but only runs on high if T-stat is set to fan. Same for either auto or manual. I was told if capacitor is bad the compressor should try to start and get warm. It does have 3 capacitors. It does not click or hum at all. The electrical board in the unit says it is a ceiling assembly part number 8330a633

      Thanks for any help you can give me.

    • profile image

      PraireFire 2 weeks ago

      Hi Randy

      Coleman 48004866 10 years old.Was working fine earlier this summer in 90 plus degree weather for about a month at the lake. Since I brought it home,it has been blowing very little cold and no heat. Replaced all 3 capacitors , cleaned fins with toothbrush. Compressor appears to be cutting in and digital thermostat seems to be working fine? Does not appear to have any freon leaks, just some minor residue on some tubing. Can a heat pump switch be the problem? If so, how do I test and where to locate it?

      Thanks, PraireFire

    • Randy Godwin profile image
      Author

      Randy Godwin 2 weeks ago from Southern Georgia

      Brian, I've sold some universal fan motors from Amazon in cases like yours. Check them out. Do you have the model number of the AC? If so it should be no problem finding a fan motor replacement.

      Randy

    • profile image

      Brian 3 weeks ago

      Hey Randy, I have an 89 Prowler and have a seized ac fan motor that I'm trying to replace I cant make out anything on the motor tag as far as a part # goes. Its a 2 speed 110 volt. Is that a standard motor? and where could I find one or a part # would be helpful. Thanks for your help.

    • Randy Godwin profile image
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      Randy Godwin 3 weeks ago from Southern Georgia

      Hey Tom. check the capacitors first. They can go bad and leak hot oil causing smoke in the process. Of course, at 12 years of age, the compressor or fan could also be suspects.

      You'll have to remove the shroud to see for sure which of the 3--or perhaps I'm wrong as there may be more--is the culprit.

      Randy

    • profile image

      Tom 3 weeks ago

      Randy

      Have a RV coleman 13500 roof top A/C started blowing smoke out of the vents and had a burning smell --12 years old, Any ideas?

    • Randy Godwin profile image
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      Randy Godwin 4 weeks ago from Southern Georgia

      Mark, check the voltage where the heating element connects first. If you're getting 110-120 volts then the element may be bad.

      Randy

    • profile image

      Mark 4 weeks ago

      Hello,my question is about the heating,the air seems to run fine but you turn the heat on runs a minute or two and kicks off same thing every time you try it.but has not ever kicked the breaker .any ideas?

    • Randy Godwin profile image
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      Randy Godwin 5 weeks ago from Southern Georgia

      Raymond, the only way to see if the compressor is bad is to use an amp meter to see if it's pulling more amps than is required. The proper amperage should be on the compressor or on a plate nearby.

      Randy

    • profile image

      Raymond 5 weeks ago

      Hey Randy,

      So, went ahead and replaced the fan capacitor. But, i was still having the same issue.

      I also double checked to see if the compressor was running and found that it was not. So, I pulled the cover off of the terminals on the compressor and found the Compressor Overload. I tested it and it had .4 ‎Ω. I'm not sure if this was the issue or not, but do you think that means its bad?

      Do you have any suggestions?

      Raymond

    • Randy Godwin profile image
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      Randy Godwin 6 weeks ago from Southern Georgia

      Connie, have the capacitors checked first to see if they've gone bad. If not, the Freon may be getting low as ice forming is not uncommon right before the Freon runs out.

      Randy

    • profile image

      Connie 6 weeks ago

      Hey Randy,

      I just bought a used Jayco camper a few months ago to live in and about 3 weeks ago it seemed there was a burning smell coming from the air conditioning unit. We turned it off and then back on about half hour later and it seemed to work fine and we didn't have any issues until about a week ago. I was asleep and I heard something that sounded like beads being slung all over the floor and it woke me up. I couldn't figure out what the noise was so I went back to sleep. The next night I heard the same thing and when I got up to search out what caused the noise I realized that there was little pieces of ice in the floor under where the a/c unit is. I turned it off that day hoping it would defrost itself and then last night it just would even cool at all. The fan works fine and when you switch on the a/c it has that burning smell again and it tries to flip on but then it doesn't, it just keeps trying without success. Any idea what I need to be looking for?

    • Randy Godwin profile image
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      Randy Godwin 6 weeks ago from Southern Georgia

      Chris, have you checked the power at the AC yet? I assume you've already checked the breaker.

      Randy

    • profile image

      Chris 6 weeks ago

      Hello I need some help I came home today which I'm a full time Rv r my air conditioner has no power so I can't even get power to the control panel any advice

    • profile image

      Raymond 6 weeks ago

      Hey Randy,

      My AC does have 2 capacitors. The one that i replaced was the Start Capacitor (It was the larger one). Do you think that even though the fan is running fine, that my issues with my AC cooling could be due to the fan capacitor not functioning fully?

      I will double check the compressor.

      Thank you,

      Raymond

    • Randy Godwin profile image
      Author

      Randy Godwin 6 weeks ago from Southern Georgia

      Raymond, your unit may have two caps. one to start/run the fan and the other to start/run the compressor. You should be able to hear the compressor kick on or feel it running. It should get rather warm if it's working.

      Randy

    • profile image

      Raymond 6 weeks ago

      How do i check and see if the compressor is running?

      I have not. I figured since the fan was running and the diagram said that one was the fan capacitor, that it was fine. Is that not the case?

      Thank you,

      Raymond

    • Randy Godwin profile image
      Author

      Randy Godwin 6 weeks ago from Southern Georgia

      Raymond, is the compressor running at all? Have you tested the other capacitor?

      Randy

    • profile image

      Raymond 6 weeks ago

      Hey Randy, Thanks for the help. I pulled off the plastic cover and fired up the A/C. The fan turned on just fine so i assumed it was the other capacitor, the run capacitor, as my Coleman - Mach only has 2 Capacitors. I ordered the exact same capacitor and installed it. However, it ac still runs the same as before. The fan will blow high and low, but it doesn't cool. Any ideas?

      Thank you

      Raymond

    • profile image

      wally kuhns 6 weeks ago

      Thx for the reply. I pulled the casing and the solder points look fine on the jack where the power cord plugs in. I will trace the wiring further back tomorrow

    • Randy Godwin profile image
      Author

      Randy Godwin 6 weeks ago from Southern Georgia

      Wally, I'd check the connections on the 120 volt AC wiring where it enters the fridge.

      Randy

    • Randy Godwin profile image
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      Randy Godwin 6 weeks ago from Southern Georgia

      Cannot tell you what gas is presently used in your ac, elcaballero. Whatever was originally used can be converted.

      Randy

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      wally kuhns 6 weeks ago

      Randy - I recently acquired a used Dometic CF50. This portable refrigerator/freezer runs on either 12V or 120V. My unit runs fine on 12V, but no lights or cooling occurs when I plug into 120V. Where do I start troubleshooting? Thank you

    • profile image

      elcaballeroandante52@hotmail.com 6 weeks ago

      wath is the gas sustitute of rv a/c dometic mod. 1984 in travel trailer Vanguard?

    • Randy Godwin profile image
      Author

      Randy Godwin 7 weeks ago from Southern Georgia

      Justin, have you checked the 12 volt breakers/fuses. The thermostat operates on the 12 volt system as does the fridge and HW heater thermostats.

      Randy

    • profile image

      Justin Bruce 7 weeks ago

      Hi Randy,

      This weekend our ac/heat unit suddenly quit working. No power to the thermostat. I checked the breakers and changed the 15 amp fuse for the furnace. Still nothing. No fan, ac, or furnace. Any idea what I can check next? Thanks in advance.

    • Randy Godwin profile image
      Author

      Randy Godwin 7 weeks ago from Southern Georgia

      Brian, you'll have to figure which wires act as a thermostat positive connection. You'll need a thermostat wiring diagram unless you simply rely on trial and error.

      Randy

    • profile image

      Brian 7 weeks ago

      I'm working on my duo-therm. I took it off my camper to work on it back at home. How do you wire it up on a test bench without a thermostat?

    • Randy Godwin profile image
      Author

      Randy Godwin 7 weeks ago from Southern Georgia

      Raymond, a new capacitor will probably do the trick. Running an AC from a generator pulls a lot of amps and a weak cap won't do the job.

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 7 weeks ago from Southern Georgia

      Carol, follow the thermostat wires as they connect to the control board. Usually an easy replacement with plug ins. You'll probably locate it under a panel where the power is supplied.

      Randy

    • profile image

      Raymond 7 weeks ago

      Hey Randy,

      I have a pop up camper with a roof ac unit. I took it down to the coast to help with the relief after Harvey. We hooked it up to the generator and it blew on high for a couple minutes then it stopped cooling and only the fan would work. Ive been told that the a capacitor could have blown due to a non grounded generator.

      Any thoughts on that?

      Thank you,

      Raymond

    • profile image

      Carol 7 weeks ago

      Hi Randy,

      Where would this control board be found in the AC unit if I removed the shroud? Could I locate it and get a replacement for it and try to install it myself?

      Thanks,

      Carol

    • Randy Godwin profile image
      Author

      Randy Godwin 7 weeks ago from Southern Georgia

      Holly Jo, the smell may have been the capacitor leaking oil when it failed. Remove the shroud on top of the AC and check the capacitor for failure. It should be distorted and the leaking oil should be apparent. If not, either have it checked or replaced. An easy and inexpensive chore in most cases.

      Randy

    • profile image

      Holly Jo 7 weeks ago

      ok so yesterday i smelled a weird smell and the lights dimmed as the AC unit turned on like it was trying to power up and couldn't. so I shut it off for the night then in the morning I tried to turn it on again the fan ran then the unit surged like it wanted to but the compressor just hummed...any ideas?

      I have a 1998 Newmar 5th wheel with ducted AC

    • Randy Godwin profile image
      Author

      Randy Godwin 7 weeks ago from Southern Georgia

      William, have you changed the compressor capacitor yet? An easy to change and relatively inexpensive part to see if the compressor is bad.

      Randy

    • profile image

      William Lanier 7 weeks ago

      Colemann mach a/c unit on trailer won't work

      thermostat seems ok,inside blower ok,compressor fan works,but the compressor does not go on,was working two week ago

    • Randy Godwin profile image
      Author

      Randy Godwin 7 weeks ago from Southern Georgia

      Carol, this could be a bad control board in the AC itself. Even if power is good at the AC end. a bad control board--not to be confused with the control box you installed--will not allow the unit to operate properly. Feel free to ask for more info.

      Randy

    • Randy Godwin profile image
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      Randy Godwin 8 weeks ago from Southern Georgia

      Thanks Jim,and pleased to help. :)

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 8 weeks ago from Southern Georgia

      Doug, try changing the capacitor(s) or least have them checked if you don't want to do it yourself. While the unit is turned off use a multimeter set on OMS with the probes touching the terminals. The common should be marked. If the capacitor is good you'll get a random nuber which decreases in value. If bad you'll either get a zero or other steady number. Hope this helps.

      Randy

    • James Gastom profile image

      Jim Gaston 8 weeks ago from Gulf Coast Fl

      Randy thanks for your response to my issue.After closer observation I was able to differentiate a very shuttle change in fan speed. I would have thought the fan would slow down a bit more than it does.

      The good news is the system cools very well.

      Thanks again for your help...Jim

    • profile image

      Doug 8 weeks ago

      Randy,

      I have a 99 5th wheel, 30 amp, 1 ac. cooling just fine for about 30 minutes then making noise and quit. I changed out the fan. Now it cooling good for about an hour then flipped the ac 20 amp breaker. Any ideas.

      Thanks

    • Randy Godwin profile image
      Author

      Randy Godwin 8 weeks ago from Southern Georgia

      Jon, this sounds like a bad compressor but you can't tell for sure unless you test it with an amp meter. The proper amps the compressor pulls should be listed on or near the compressor. This could also be a thermostat or control board problem. The process of elimination still works in these cases. :)

      Randy

    • profile image

      Jon 8 weeks ago

      My A/C compressor kicks on but only for a few minutes then it shuts off and just blows air. I replaced all 3 capacitors and it is still doing it. It is a 30 amp w/ shedding and it is not shedding at all, the compressor just shuts itself off.

      It is a 97 degree day today and we live in our RV, so it should be on non-stop. It is a Coleman unit.

    • Randy Godwin profile image
      Author

      Randy Godwin 8 weeks ago from Southern Georgia

      Jim, I hesitate to suggest a new control board unless you rule out the thermostat first. It's possible your unit has a separate fan control but it's not likely. Have you looked underneath the shroud yet to see if there's such a relay yet? There may be a wiring diagram on the unit or you can probably find one online using the model number. I'd be interested in what you find out or if any of my suggestions helped. Thanks!

      Randy

    • James Gastom profile image

      Jim Gaston 8 weeks ago from Gulf Coast Fl

      Yes it is a liquid crystal digital and no matter what I move the fan speed the blows on high

    • Randy Godwin profile image
      Author

      Randy Godwin 8 weeks ago from Southern Georgia

      Hey Jim, usually there's a problem with either the thermostat or the control board when the fan doesn't work properly. Is this a wall mounted thermostat?

      Randy

    • James Gastom profile image

      Jim Gaston 2 months ago from Gulf Coast Fl

      I have a duo therm roof unit that was replaced July a year ago by the previous owner.

      I notice the blower only works on high speed in spite of it also having a low and medium control on the same thermostat.

      This unit also has a heat strip which also only has a high speed operation.

      Can you give me any help on getting the other speeds to operate?

      Thank You Jim

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Michelle, you may have a bad heating element in the unit. Replacement is not difficult at all. In most cases the element simply plugs in.

      Randy

    • profile image

      Michelle Kurle 2 months ago

      We have a Air V Carrier for our horse trailer. The unit fits on the ceiling. The air conditioner works but could be colder, but when we turn on the heat it blows but not warm or hot. Any ideas on what to do

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Carol, it may be either the thermostat or the control board. I'd check the thermostat first.

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Do you mean the awning, Red?

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Keith, it's possible the heating element is burned out. An easy replacement job, if so.

      Randy

    • profile image

      Carol 2 months ago

      Duo Therm with ceiling manual T-stats control stop working only humming sound on both Fan and Cool when it's "ON" position. Replaced both fan and motor run capacitor. Problem worsen. Doesn't even hum now or try to turn on. Check all the breakers on panel looks good. Check 12V for battery good. Check 120V coming in good. Any clues or ideal Randy?

      Thanks for having this thread running for so long. Very helpful!

    • profile image

      red 2 months ago

      how do I troubleshoot my owning

    • profile image

      Keith 2 months ago

      My duo therm unit does not blow hot air. Any ideas

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Hey Steve, have you checked the thermostat yet? It's not uncommon for a thermostat to fail. If it's not the thermostat then the control board may be the culprit. Since you've already changed the fan capacitor and the fan runs when turned to ON, I see no other options.

      Randy

    • profile image

      GrandpaSteve 2 months ago

      Coleman Mach cooled but fan did not run in auto or on positions unless the squirrel cage was bumped by hand. Motor spins free but would not restart when in auto and T-stat calls for cool. It would run in fan on position.

      Changed fan capacitor and automatic mode worked properly for a few days and now fan won't come on in automatic. Switch to on and fan runs and unit cools.

      Where do I need to look next?

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Tony, it could be the thermostat or the control board. Check the thermostat first.

      Randy

    • profile image

      Tony 2 months ago

      I have a Salem the air conditioner won't shut off automatically no matter what temp I put it on. Just stays on. Can anybody tell me what

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Your wife may be right, James. A new capacitor is cheap and worth a try before replacing the fan.

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Chris, check the compressor capacitor as this may be the problem.

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Ian, check or replace the capacitors first.

    • profile image

      James dewitt 2 months ago

      I have a 2004 Alpenlite 5 th wheel with a heat pump, I have to nudge the fan. And after that it runs like a charm. I think I need a new mother my wife wants to change capacitors. Any thoughts

    • profile image

      Chris davis 2 months ago

      Hi Randy I have a 2007 kz. The ac will turn on and blow on fan and on ac. Hight or low. I do not hear the compressor kicking on at all. Only hot air will come out. If I turn the ac on and it's blowing air even if I mess with the thermostat put it up to 90 still blows don't shut off and won't blow cold.

    • profile image

      Ian 2 months ago

      2010 Winnebago Itasca. Rear rooftop Coleman air starts and runs blowing cold air for about 3 mins. The blower fan then stops but unit still runs for a couple more mins before shutting down.. Thermostat seems to work fine. Come back in 15 mins and try it again and it does the same thing.

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      It does indeed seem the thermostat is faulty, Mike.

      Randy

    • profile image

      Mike 2 months ago

      Still have issues, however I did find that I can touch the two thermostat wires to the furnace together and it kicks on, and if I put a jumper from R to Y my AC unit comes on. The red wire get hot if it's on heat, but having the theomostst hooked up normally, all that will come on it the fan on the AC unit. Any suggestions as to what may be causing this? I figured the thermostat may be defective, because I will told by mautiple RV service people that the thermostat I have will work in a camper, I went as far as replacing my wires from my AC to the thermostat and still only get the fan. Placing jumper wires everything works as it should but won't shut off unless it's disconnected. I had a Honeywell RTH2300b installed with my new AC unit and the control box is all brand now.

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      John, it could be a bad capacitor. An inexpensive and easy replacement in most cases.

      Randy

    • profile image

      John 2 months ago

      I was camping and the ac stopped cooling I switch to the back ac tell I could get up on the roof I seen that it was wet around the ac so I tried to start the ac and the fan would turn on but no cold air what could be wrong with it

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Brian, a weak capacitor will cause this problem, especially when powered by a generator.

      Randy

    • profile image

      Brian 2 months ago

      hello randy,

      my main cabin ac will not turn on. With the generator on, I turn it to high and cool. You can here the generator surge a little like it is drawing from it. Under the ac unit it makes a loud humming noise and acts like it wants to turn on but does not. the rear ac works fine

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Wade, more than likely it's the thermostat or the control board causing the problem. Have you checked the thermostat voltage yet?

      Randy

    • profile image

      wade 2 months ago

      compressor running with thermostat turned off

    • Randy Godwin profile image
      Author

      Randy Godwin 2 months ago from Southern Georgia

      Brad, I assume you've checked the thermostat if you have a wall mounted model, so that only leaves the control board or a bad compressor. It seems odd though that the compressor was working fine when you turned it off before the two week absence. Does the AC do anything at all, make noise, try to start, etc?

      Randy

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      Brad Langley 2 months ago

      coleman ac unit turn off left for 2 weeks came back compressor would not start up replaced all 3 capacitors compress still won't start it is an 08 year model might be time for a new on don't what else to check any suggestions

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      Randy Godwin 2 months ago from Southern Georgia

      Rodney, try replacing the fan capacitor and see if this solves the problem.

      Randy

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      Rodney 2 months ago

      Hi Randy. I have a 2006 Dutchmen 31ft with a Dometic Duo Therm that started making a funny noise, but every time I restarted the ac act like normal. Yesterday the ac was making that noise again, the air it is not blowing so strong as should be. It looks like still blowing cold. I try the fan only, and looks like the fan is not blowing strong. Any chance could be something easy to fix?

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      Randy Godwin 2 months ago from Southern Georgia

      Jay, sorry the new fan motor didn't fix the problem. Are you sure the breaker is good?

      Randy

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      Jay 2 months ago

      Hello Randy. I've been very busy and actually just got around to installing a new fan motor. Unfortunately, I do not have good results.

      The install was a bit of a pain because the A/C unit is very old. There was no way for me to access the squirrel cage to loosen the motor on that end because it was shielded all around and sealed; so I cut into the encasement and was able to access the screw on the squirrel cage at that point. (When I finished replacing the motor, I used aluminum tape to seal the opening that I cut and bent open).

      Well, the end result was that the breaker still trips. I've replaced 2 capacitors and the fan motor & fan blade. I think I'll call it a day and decide if I'm willing to spend another $500-$600 on a new unit, then spend half the day removing the old and installing the new.

      Thank you for your input. It was most appreciated.

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      Randy Godwin 2 months ago from Southern Georgia

      Doug, try using some good no-rinse spray coil cleaner as dirty coils can cause the unit to disperse the moisture onto the roof or down through the filter.

      Randy

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      Doug 2 months ago

      I have a 2007 Jayco Eagle with a Coleman AC unit. Water from the condenser runs out on to the roof of the camper. Is this normal.

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      Randy Godwin 2 months ago from Southern Georgia

      Dustin, was it blowing cold air before the cleaning?

      Randy

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      Dustin Acker 2 months ago

      Anyone have any ideas why it won't blow cold air after cleaning?

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      Randy Godwin 2 months ago from Southern Georgia

      Shelly, sounds like low voltage or amperage. What power are you connected to?

      Randy

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      Shelly 2 months ago

      Hi, I have a 2000 Southwind that has 2 ac units.

      The units shed and then after a few minutes they keep shedding and slowing lose power to both acs.

      They will both work individually but not together properly.

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      Randy Godwin 2 months ago from Southern Georgia

      Mark, it could be a weak breaker, but it could also be a weak capacitor. A cap is cheap and easy to install so I'd try that first.

      Randy

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      Mark Carey 2 months ago

      I have a Dometic unit which starts and runs normal for about 5 minutes before it trips the AC breaker. It is producing cold air and the motor is working fine. Coils and everything are clean. Could it be a faulty breaker?

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      Randy Godwin 2 months ago from Southern Georgia

      Mark, this may be the capacitor or the compressor. Try replacing the capacitor first--about $20 or so--and if this doesn't solve the problem then the compressor is bad.

      Randy

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      mark 2 months ago

      Fan works and it appears there is a power surge as the compressors tries to start. All lights go dim for 3-4 seconds and then returns to normal but no compressor start.

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      Randy Godwin 2 months ago from Southern Georgia

      Tia, yes a system can leak coolant over time. If the compressor is running the thermostat is probably fine.

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      Tia Seibel 2 months ago

      capacitor works and it sounds like the compressor starts up, however the air does not get cold. Does a system lose coolant or could it maybe be a thermostat?

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      Randy Godwin 3 months ago from Southern Georgia

      Tom, I'd change the capacitor first as it's a cheap--around 20 to 30 dollars--and easy replacement before looking at the compressor or control board. Is it a wall mount thermostat? If so, you need to check it as well.

      Randy

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      Tom Smith 3 months ago

      I have a 1990 Dometic duotherm rooftop unit. The fan works as it should but the compressor doesn't start. It appears to have only one capacitor for both. Is it possible that the capacitor is at fault or am I looking at a compressor or control board problem.

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      Randy Godwin 3 months ago from Southern Georgia

      E. Wheeler, simply because a capacitor is new doesn't mean it won't fail. If you have a digital bolt meter I can instruct you how to test the capacitors. As for the overhead ducts, if your camper has a few years on it it's possible some of the ducts have collapsed. I've observed this happen more times than I can remember. You might try removing the vent covers and see if you can run a small rod of some sort to see if you vave the same problem. And yes, ants can affect electrical components sometimes.

      Randy

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      Randy Godwin 3 months ago from Southern Georgia

      Sorry Debra,I don't understand your question. Care to try again?

      Randy

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      Debra 3 months ago

      Have a Duo therm unit air or heat want come on checked the fuse on the board in the box in the ac it was blower everyone we replace it it blows

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      E. Wheeler 3 months ago

      Can bull ants get into your roof ac & affect your operation ?

      Fan run & no compressor ?

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      E. Wheeler 3 months ago

      Hi,We have a 36' Newmar Mountain Aire.

      AC was pre-trip professionally serviced & installed new fan blades, & starting capacitor. Ran at home for wks before trip. Dometic 13,000

      Went for weekend, all well til woke up 80'F. fan was blowing. . Camp electric 50 amp ck'd ok. What's up?

      Is it necessary to keep backup capacitors for your rig ?

      Also what volume of air should you expect to flow out of your ac overhead ducts-our high volume flow feels slow & inside cabin feels still & compared to our Holiday Rambler & Airstream Excella ac's of past.