Troubleshooting and Maintaining Your RV’s Air Conditioner

Updated on December 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 rooftop air conditioners used on motorhomes are made to give many years of dependable cooling efficiency, especially if you maintain them.

This article has two parts: first, how to troubleshoot your AC and decide which parts to replace or service; and second, how to maintain your AC.

These repair and maintenance tips are very simple to follow, even for those without much hands-on experience.

Part 1: Troubleshooting

Some Background: How Your AC Works

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

Briefly, your air conditioner, which may be combined with a heating system, includes a compressor—to circulate a cooling fluid like Freon through the coils and fins of the condenser—and a fan, to blow cooled air through the RV. The fan and compressor are turned on and off by a thermostat—a switch attached to a thermometer—and kick-started by one or more capacitors. The thermostat and other controls are run by the vehicle's 12-volt electrical system.

Where to Start Investigating

Many problems your air conditioner might have—sluggish behavior, turning off prematurely--can be resolved by checking out the electrical system in order, going first through the possibilities that are easiest to resolve. These easier choices often solve the problem. If they don't, you can investigate further so you can decide if you need to replace the big items like the fan and the compressor or get a whole new AC unit.

First, we'll address the common electrical issues.

A Precaution

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.

RV AC Issues You Can Troubleshoot Yourself

  • If your AC does nothing and makes no noise, make sure your unit and its controls are getting power.
  • If your AC fan or compressor is slow to start, doesn't blow any air, blows weakly, blows only warm air, stops after a while, dims your lights, or trips your breaker, you should first check your capacitors and replace them if needed. 

  • If there's no air blowing, check the fan capacitor; if there's no cooling, check the compressor capacitor.
  • If the capacitor is okay, you should look at whether the thermostat is getting power by checking whether the 12-volt appliaces work.
  • You can check the function of the thermostat if it's wall-mounted. If the unit only works when thermostat wires are touching, the thermostat is bad. The thermostat is easy to replace.

  • If the capacitor and thermostat are okay, the control board may be bad.
  • If the control board is okay, you may have to replace the fan motor or the compressor.

  • If the fan only works at certain speeds, the fan motor may be bad.
  • You can have the fan motor rebuilt (if it's not the sleeved-bearing type). Or you can replace the fan motor yourself if the unit is in good shape otherwise.
  • If the compressor is bad, it should probably be replaced, not fixed.
  • If your system drips or overheats, the coils may need cleaning.
  • If the roof AC leaks, the bolts may be loose or the gasket may be leaking.
  • If the system is very cold or ice builds up, it may be low on Freon.
  • If the unit is noisy, something out of place may be interfering with its motors; you can check by removing the shroud.

The First Step: Is There Power?

If your unit does not react at all—does not go on and does not make noise—you will want to make sure it is getting power. Look in the 12-volt panel and check that the fuse has not blown or the breaker has not tripped. The 12-volt power system runs the controls to the AC including the thermostat.

Running the AC unit itself draws a lot of higher-voltage power, maybe too much for a 15-amp power pole, and if there are two modern rooftop units they may draw too much for the 30-amp power supply provided at many campgrounds. If the unit draws more than the system can provide, the breaker or fuse will shut off. Fortunately, many campgrounds and RV parks now provide 50-amp service for modern multi-unit AC systems.

The thermostat is run by 12-volt power, like your motor home's lights and vent fans. If these accessories aren't working either, there is something wrong with the 12-volt power. A breaker may be bad or there may be a loose connection in the breaker box. Occasionally the power converter that converts your higher-voltage power to 12-volt power is bad.

Next: Consider the Capacitors

If the fan or the compressor fail to start, it is possible the starting capacitor is malfunctioning. A bad capacitor can cause a variety of symptoms: the AC unit merely hums and "tries" to start, it runs a few minutes then trips a breaker, the fan won't start without a push, or it blows only hot air because the compressor can't start.

The capacitor stores electricity to give both the fan motor and the compressor an extra boost whenever the RV AC unit starts. It is not unusual for the capacitor to go bad, especially if the RV sits unused for a while, and not be able to provide that little push that gets the motors going. On occasion a bad capacitor will explode with a puff of smoke without damaging the rest of the unit.

There may be one capacitor for both compressor and fan, two capacitors (one for each part), or even three or more all together. A capacitor is often shaped like a small battery, flask, or button.

If you have a multimeter in your tool kit, you can use it to test the capacitor. A good capacitor should show a random value on the multimeter that slowly decreases the longer you keep the probes in place.

A bad capacitor is easy to replace. Check the required voltage and model numbers on the old capacitor when ordering a new one.

When replacing it, make sure the power is off. Observe which wires go into it where, and make a note so you can install the new one exactly the same way. Don't touch its terminals with your bare hands. Before you throw the old capacitor away, drain out its electrical charge by connecting its terminals with a screwdriver (make sure the screwdriver handle you are holding is insulated).

Very often, your AC unit will start and run fine after you replace a capacitor.

A capacitor.  Often a cylindrical container, but yours may differ.
A capacitor. Often a cylindrical container, but yours may differ. | Source

Next: Check the Thermostat and Switches

A bad thermostat is another possibility. If you have a wall-mounted thermostat, you can check it by checking its voltage with your multimeter. If the unit only goes on when you touch the thermostat wires to each other, the thermostat is definitely bad.

If the thermostat and capacitors are all okay but the AC still doesn't work, you may have a bad control board.

Thermostats and switches may be purchased online by finding the correct model and serial numbers before ordering the new parts. These items are easy to replace in most cases. As always, make note of and remember the wiring connections when replacing these electrical components.

Is Your Fan or Your Compressor Bad?

If after you check these electrical items your AC still doesn't blow out air, or it blows only at certain speeds, your fan motor may be bad. If your AC blows but only hot air comes out, your compressor may be bad. Sometimes—not necessarily—a fan or compressor smokes or leaks oil when it goes bad.

A compressor that is working should turn on audibly and feel warm to the touch. You can test a compressor with a clamp-on ammeter, if you can rent or borrow one. Check how many amps the compressor is drawing. If it draws much more current than the amp rating written on the unit or on a nearby plate, the compressor is toast.

You May Be Able to Rebuild or Replace Your Fan Motor

Oiling your fan motor, as shown in Part 2 of this article below, will help it run more easily. If your AC fan motor is slow to start even after oiling, or needs a nudge to get it going, or only runs at certain speeds, or doesn't run at all, it will need to be rebuilt or replaced.

Fan motors come in two types: with exposed bearings which may be lubricated easily or with sleeved bearings (see the last photo in the article). The first type of fan motor may be rebuilt fairly cheaply and will last for many more years. But not so a sleeved-bearing AC fan motor.

Unlike fan motors with bearings, a fan motor with sleeves cannot be rebuilt economically, and must be replaced with a new one if it goes bad.

If your AC unit seems to be in pretty good shape otherwise, you can order a new AC fan motor to fit your particular unit. There are many sizes and models to choose from. Check the numbers on your old motor. By looking at pictures and descriptions on Amazon you may be able to identify a universal motor that will fit your unit.

Replacement of the AC fan motor is a simple job requiring only a few tools. If the electrical connection to the motor isnt a simple plug-in, mark down the colors of the wires before removing the old fan motor.

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

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.
Model and serial numbers on RV AC fan motor
Model and serial numbers on RV AC fan motor

A Bad Compressor Isn't Usually Worth Fixing

Compressor
Compressor

If, after you determine that the switches, capacitor, and relays are not at fault, the RV AC compressor fails to operate correctly and cool your air, 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 likely be too expensive a repair. Under normal circumstances a compressor will last much longer than its warranty.

It May Be Simpler to Replace the Whole AC

If after investigating these possibilities you decide your old RV AC unit has enough problems to need 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.

Some Miscellaneous AC Problems and What May Cause Them

If your AC does run, but only with problems—overheating, dripping, being way too cold—you can address these problems too.

  • Overheating may be due to a simple failure to clean the coils—something I show you how to do in the second half of this article. When the coils are clean they can disperse excess heat into the air.
  • If water leaks into your unit and seems to come from the AC, investigate to see where it is coming from. The leak may come from the gasket between the unit and the roof; if so, it's easy to address. Tighten the bolts carefully, and if that doesn't work, replace the gasket.
  • Dripping from the unit itself may be caused by water condensing in the wrong place (in the pan under the air conditioner) instead of being evaporated by the fan. Such water buildup may be due to dirty coils, and if so, you can cure it by cleaning the coils.
  • If your unit blows very cold and builds up ice—and especially if it later stops cooling at all—it may be low on Freon. Sometimes you can see a visible oily residue around a Freon leak. You may be able to add Freon to your system yourself with a self-piercing valve.
  • If your motor is noisy, you can investigate the problem by taking the shroud (the cover) off the roof AC unit and seeing if everything is in place. The rubber shock absorbers on the compressor and fan may be interfering with the motion of the unit.

Part 2: Maintenance

Accessing the Condenser and Evaporator Coils to Clean Them

Removing the RV AC shroud retaining bolts
Removing the RV AC shroud retaining bolts

Maintenance gives your AC longer life and better efficiency. Roof air conditioning units on motorhomes are the same as ones used on other types of RV campers such as travel trailers and pop-up campers. These repair and maintenance procedures are identical for all these types of campers.

After a few seasons of use, it isn’t unusual for the AC unit to not cool the motorhome as quickly or as efficiently as it once did. Even if you clean the filters regularly, 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 (above) by unscrewing the four bolts securing it to the RV AC unit itself.

How To Clean the RV AC Coils

This coil is badly in need of cleaning
This coil is badly in need of cleaning
These coils are badly in need of cleaning too.
These coils are badly in need of cleaning too. | Source

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.

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

Follow the instructions carefully for the best results. A good wet/dry Shop Vac will help you clean up afterward and 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.

Air Conditioner Fin Comb
Air Conditioner Fin Comb

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

 

Maintaining the AC Fan Motor

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

While the RV AC shroud is removed, it is a good time to service the fan motor and clean the fan itself. 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, there will be oiling ports at each end of the motor. It may be necessary to remove the metal sheeting over the top of the fan motor, plus a few sheet metal screws, to access the bearing oiling ports.

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

Covering Your Motorhome AC Unit in the Off-Season

Your motorhome AC unit should give you many seasons of dependable operation if serviced annually. It's good to put a cover over the AC unit during the times when the motorhome is not in use.

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

Questions & Answers

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

        Russ, if the unit leaks only when raining then the gasket needs replacing or tightening. There should be 3 0r 4 bolts you can tighten which seals the area the unit is sitting on. The bolts may not have been properly tightened when the unit was installed.

        Randy

      • profile image

        rick rusaw 2 days ago

        2017 forest river motorhome. slight use, Atwood AC drips condensate when it rains. otherwise OK???

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

        Greg, have the other caps tested or you can do it yourself with a multimeter. Set it on ohms and if you get a random number decreasing in value the cap is good.

        Randy

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

        Randy, this could be either the thermostat or the control board. Check the thermostat first before ordering a new control board.

      • profile image

        Greg knowles 5 days ago

        Randy,

        I replaced the fan capacitor like you said and the unit now comes on for about 2 seconds then shuts off. Should I replace the other 2 capacitors or is it now control board or thermostat.

      • profile image

        Randy 6 days ago

        I have a 2003 Cougar 5th wheelwith a Dometic ac unit and themostat. The ac compressor runs all the time with the thermostat turned to off, furnace or ac. Fan speed can be changed from high to low and furnace runs fine. Any suggestions?

      • profile image

        Harry 2 weeks ago

        Thanks found it

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

        Harry, the control board is located in the unit itself and receives the info from the thermostat as to what mode is preferred.

        Randy

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        Harry 2 weeks ago

        control switch is on the same unit as the thermostat the switch also can turn on the heater or fan

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

        Harry, more than likely it's a bad thermostat or control board problem. Check the stat first before replacing the control board.

        Randy

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        Harry 2 weeks ago

        a few days ago I heard the unit come on on my RV but the noise was on the roof. When I checked the thermostat control was not turned on, but then the unit on the roof turned off and the lights dimmed . I checked the control again and the unit was in the off postion . the unit came on again so I unplugged and the unit turned off . I'm confuessed

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

        Vernon, more than likely the fan is now out of balance and is causing the overload to kick.

        Randy

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        Vernon collins 2 weeks ago

        The motor fan blades broke off. Domestic model457915 . Will that cause the unit run a short time with warm air and then trip terrain breaker?

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

        Jackie, this does seem to be a puzzle. You seem to have replaced all of the pertinent parts so it may be in the compressor itself. Sorry I can't give you better advice.

        Randy

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        Jackie Everett 3 weeks ago

        Randy,

        Need you help! I have two heat pumps on my motorhome. One is working perfectly the other is working fine when you turn it to heat but it will not cool. Fan runs but compressor will not run. Changed thermostat and control board, still same issue. Jumpered out the COOL SHED on the control board, same issue. Compressor running fine on HEAT, why will it not come on COOLING!!

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

        Eric, more than likely the control board is at fault. The stat sends a signal to the control board and it controls the fan motor speed.

        Randy

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        Eric 3 weeks ago

        Randy,

        The fan on my AC unit runs at the same speed whether it is in high or low. I replaced the thermostat but there was no change. Any ideas?

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

        Greg, have the capacitors checked and/or replaced. A bad capacitor will cause this problem.

        Randy

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        Greg knowles 4 weeks ago

        When turning on a/c low hum and clicking sound, nothing else.

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

        Hi Nick, this may be a thermostat or control board problem if the AC is running properly otherwise. I'd check the thermostat first.

        Randy

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        Nicholas 4 weeks ago

        Hi randy first thing it’s so nice of you to be helping others for free

        We just moved into a 07 heartland and our AC will kick in and then kick off. I have the thermostat all the way down on 40 because it will not turn on any other way.

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

        Kim, this could be either the thermostat or the control board. I'd change the thermostat first before replacing the control board.

        Randy

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        Kim 5 weeks ago

        Ac will not shut off automatically....

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        Joanie Ready 5 weeks ago

        Thanks for the quick reply. I knew that's how our home one is. Appreciate the help.

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

        Dean, this could be several things, including the thermostat or control board. Check the stat first as this is the easiest--and in some cases--the most economical part to replace. Let me know if you need more info.

        Randy

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

        Joanie, the control board is located in the AC unit itself and receives the signals from the thermostat. I'd check or replace the stat first before ordering a new control board.

        Randy

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        dean 5 weeks ago

        air conditioner cuts on and cools off but when it cuts off it sounds like the fan is running and then it won't cut back on and then throws the breaker

      • profile image

        Joanie Ready 5 weeks ago

        Also, is the control panel you speak of on the thermostat or the unit. Familiar with house unit control panels but not RVs.

      • profile image

        Joanie Ready 5 weeks ago

        Our air conditioner in our camper does like Barbies in that you have to turn the thermostat down to 40 for it to come on. It gets very cold, but even if you turn the AC to off the compressor will continue running for 10 minutes or so then it comes back on. We had to cut power at the breaker to stop it. Any suggestions?

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

        Rebecca, there may be two breakers controlling the furnace and the AC. At any rate, the thermostat is controlled by the 12 volt system.

        Randy

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        Rebecca 6 weeks ago

        Power is off to breaker but when thermostat is on furnace the air is working why

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

        Jimmy, this may be a low Freon charge. Can you tell if the compressor is kicking on or not?

        Randy

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        jimmie l 6 weeks ago

        what would be the problem if A/C not blowing cold air in the day but blowing warm air, but coils not dirty ,blowing air good on low in high settings on thermostat with no problem, condenser hot to touch, fan is blowing air out evaporator coils. It seem to get little cold during night night

      • Randy Godwin profile image
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        Randy Godwin 7 weeks ago from Southern Georgia

        Kenny, this sounds more like a thermostat or a control board issue than a relay. I'd check the thermostat first.

        Randy

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        Kenny 7 weeks ago

        Hi my AC in staying on on the roof as the inside shuts off. Also when I turn the thermostat off the condenser stays running which freezes up to coil . Is this because of a relay

      • Randy Godwin profile image
        Author

        Randy Godwin 8 weeks ago from Southern Georgia

        Hey Barbie, if your unit has a wall mounted thermostat it may be out of calibration or is malfunctioning in some manner.

        Another possibility is the control board--which receives the proper signal from the thermostat--is bad.

        I'd recommend changing the thermostat--even if it's on the unit itself--before investing in a new control board. Hope this helps. :)

        Randy

      • profile image

        Barbie 8 weeks ago

        Good evening Randy.. we are having an issue with our ac in our Dutchman.. the ac will not come on unless we drop the thermostat down to 40 degrees.. cools for a while and then it shuts off.. definitely not 40 degrees in the Rv.. what’s your thoughts?

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

        Ed, if your AC uses a wall mount thermostat, it may be the problem. If it's not the thermostat then the control board may be the problem.

        Randy

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        ED MARTINEZ 8 weeks ago

        My RV AC unit start for 20 min. and stop,... when I put it on again, the green light its flashing and doesnt start..

        capacitor ok, compressor ok, terminal has continuity

        Can you help me to do this ...please

        thanks

      • Randy Godwin profile image
        Author

        Randy Godwin 8 weeks ago from Southern Georgia

        Julie, the only thing I can think of is a bad control board in the unit. The thermostat seems to be working properly as the other unit is okay.

        You can try replacing the control board but I cannot guarantee it is the problem.

        Randy

      • Julee Ellison profile image

        Julee Ellison 8 weeks ago

        Hey Randy ... Julee the trouble maker checking back in. The front a/c is still working, but now the bedroom a/c has stopped working again. As I said in my earlier post, we replaced both capacitors, checked the coils (they were clean) and blew out a little dust and a few leaves. After doing that, and turning off/on the breaker, it started working again ... but has once again stopped working. The fan runs when you turn the fan from ‘auto’ to ‘on’, but the a/c once again will not run.

        Here is something we just tried ... we opened up the ceiling unit ... and lightly banged on the little box that all of the wires run to, but that didn’t work. I had read somewhere to try that, but no dice. Any other ideas of what we might try? I hate calling the mobile RV tech, knowing he will probably charge us $200 just to come here, before he does anything. :-/

        Thanks for your time and help!

      • Randy Godwin profile image
        Author

        Randy Godwin 8 weeks ago from Southern Georgia

        Hopefully so, Julee! May have been a loose connection.

        Randy

      • Julee Ellison profile image

        Julee Ellison 8 weeks ago

        Randy, when we left yesterday, I tuned the front a/c on (setting it to 72 degrees), ut also turned on the fan, so if the compressor did keep running, the fan would keep it cool. We got home last night and I shut the a/c off at the thermostat, and the compressor has now stopped running when turned off at the thermostat. Maybe running the fan all day rattled it back as it should have been?

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

        Christie, the filter goes beneath a cover on the ceiling mount.

        Randy

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        Christie 8 weeks ago

        Where does the. Air filter go?

      • Randy Godwin profile image
        Author

        Randy Godwin 2 months ago from Southern Georgia

        Julie, it is possible the shaking disturbed the AC's, but usually they are made to be shaken during the trips back and to the RV sites.

        More than likely it is a thermostat or control board issue. Is the converter keeping the battery charged as it should be? I ask because the AC thermostats are powered by the 12 volt system and so is the slide-out.

        Randy

      • Julee Ellison profile image

        Julee Ellison 2 months ago

        Hi Randy, I’ll try and keep this short, and hope you can help. We had a slide fail, and while getting it in manually, the RV took a lot of shaking. When we got to this location the next day, the back a/c stopped working. The fan worked, but no a/c. We changed out both capacitors, blew out the coils, reset the breaker and it now works. (RV is a 2015.)

        Now the front a/c is working, but when it reaches the correct temp, the air stops as it should, but it sounds like the compressor is still running , without the fan. We have checked it, and the coils are clean and there is no debris up there. Even with the thermostat in the off position, fan set to auto, the compressor sounds like it’s running. We have tried letting it sit with the breaker off to see if it would reset it, but as soon as we turn on the breaker , the sound starts back up again. Now I am starting to think that all of the rocking the guys had to do to the rig to get the slide in manually, somehow messed with both a/c units. Any ideas or thoughts, or something else we could try will be greatly appreciated. Now I’m afraid that if the compressor is trying to run without the blower, that’s we will burn up the compressor, or it will catch on fire. :-/

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

        Brant, this sounds like a weak capacitor. Change it or have it checked before doing anything else.

        Randy

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        Brant 2 months ago

        Yes I have a 2015 26' salem bumper pull camper, the a/c blows cold like it should but recently the fan motor will start making a strange noise then start to bog down and trip the breaker. What is your opinion on this and what should I look at to replace. Any help would be greatly appreciated, thank you.

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

        Patricia, check or replace the start/run capacitor before going to the repair center. Easy job and cheap cost. Hope this solves the problem. :)

        Randy

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        Patricia 2 months ago

        Hi i have a 2010 fifth wheel - the air does not start

        we changed the panel board - still the same

        we checked the fuses - all ok

        we checked the breaker - ok

        we checked that the wire from the control panel is in the unit - ok

        we did not use the unit for the last 8 months - but now we are travelling and it's warm i here, can you let me know what else i should check before going to the service center.

        thank you very much

        Patricia

      • Randy Godwin profile image
        Author

        Randy Godwin 2 months ago from Southern Georgia

        Hi Brady, is this a recent problem? I notice you've had this rv for awhile so apparently it was working properly before.

        I'll check with my "expert" tomorrow and if I find out anything I'll get back to you.

        Randy

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        Brady White 2 months ago

        Question: I'm having problems with my a/c system freezing up. I have cleaned the filter and added a service port to check the charge. It is 410A refrigerant. The suction pressure is low. If I add refrigerant it begins to freeze up. If I reduce the refrigerant it doesn't cool. I really think it is possible that this unit was labeled wrong from the factory and is designed for R-22 instead of 410A or I have a partially restricted capillary tube. The suction pressure will run around 70 lbs. without freezing up, but it doesn't cool. We purchased this r/v new in 2013. Has anyone else had a similar problem.

      • Randy Godwin profile image
        Author

        Randy Godwin 2 months ago from Southern Georgia

        Mike, sounds like a bad capacitor. Replacement cost around $20 or so.

        Randy

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        Mike 2 months ago

        my unit is on a pop up rock wood. When turned on I get a humming sound and the coils get cold but the fan is not blowing. It's a 2003 model and I just purchased it from an individual who said it worked for him

      • Randy Godwin profile image
        Author

        Randy Godwin 2 months ago from Southern Georgia

        Michael, sounds like a bad capacitor. A replacement cost is around $25.00.

        Randy

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        Michael 2 months ago

        Randy,

        Great article. I have a unit that you can turn the fan on, but as soon as you try to turn the ac on, everything stops and the fan won't even work, unless you remove power from everything.

        Thanks,

        Michael

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

        Daryl, try checking the capacitor(s) first as they may be getting weak before changing out the motor.

        It isn't too difficult to change the motor out if you have basic skills if it is indeed the problem. Good luck!

        Randy

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        Daryl 2 months ago

        Randy,

        Considering buying a replacement motor/fan kit and doing the work myself. Went on a long road trip this summer and it worked great on my 2000 Jayco Qwest 244bh. On the way home it started making chicken noises and finally would grind to a halt. Tried oiling the motor but was unsure where exactly it needed to be oiled. Worked for another night for couple of hours, then stopped running again. Just a humming noise like the motor has been seized up. Is it just the motor, or could it be anything else?

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        Randy Godwin 2 months ago from Southern Georgia

        Dawn, it seems things work fine when the tech is present for some exasperating reason. The only thing I can think of at the moment is the compressor may be pulling more amps than normal.

        You can check this with an amp meter if you can buy/borrow/rent one. The normal amperage should be found on the compressor or on a plate nearby.

        Hope this helps.

        Randy

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        Dawn 2 months ago

        My Dometic rooftop ac will sometimes just hum, then eventually start. I have had the capacitor replaced, and had it checked again, and it's good. When it is humming, I can reach up and spin the fan freely, but it doesn't force it to start. There are no critters or obstructions. I have replaced the thermostat.

        It seems to happen when I haven't used the ac for a while. I have had a mobile tech out, and of course it started working when he got here, and he couldn't find anything wrong.

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        Randy Godwin 3 months ago from Southern Georgia

        Hey Shannon, I once had different shrouds for sale on this page but the site removed them for some odd reason. You can find replacements on Amazon or perhaps a used one could be found at the local auto salvage yards.

        Clean the coils well with a good no-rinse spray foaming coil cleaner and have the capacitor(s) checked and replaced if necessary. Good Luck!

        Randy

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        Shannon 3 months ago

        I just recently purchased an older small living quarters trailer. I need to buy a new shroud for it, because the venting slats ( if that makes sense) are taped together...not super attractive. On the inside switch, there it says COLEMAN MACH, no number. How do I know what model it is and what shroud would cover it? It's been sitting for awhile at the dealership and the a/c hasn't been used. Any tips to get it in great shape before I use it a lot this summer? Thanks!

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        Randy Godwin 3 months ago from Southern Georgia

        Check the capacitors first, Ken.

        Randy

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        ken 3 months ago

        Hi my roof top ac unit comes on and runs cold but never stays on long enough to cool the entire camper

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        Randy Godwin 3 months ago from Southern Georgia

        Dan, have the capacitors checked and replaced if bad. This should tell you something!

        Randy

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        Dan 3 months ago

        Hi

        Looking for troubleshooting suggestions as our 4700 Coleman Mach air conditioner has just stopped working, it was in auto function mode when it stopped. The unit/caravan is only 2.5 years old. It doesn’t have its own circuit breaker and there is power to my caravan

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        Randy Godwin 3 months ago from Southern Georgia

        Autohaus, the problem is either the thermostat or the control board.

        Randy

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        autohaus 3 months ago

        great article, very helpful,but my problem is not listed. My ac wont shut off and it is in the auto mode, I have to through the breaker to shut it down,and the same to turn it on

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        Randy Godwin 4 months ago from Southern Georgia

        Samaya, there's obviously some sort of vibration causing the problem. It may be in the motor itself. Sorry, that's all I have without seeing the unit myself.

        Randy

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        Samaya 4 months ago

        I have a 2014 Airxcel roof top unit on a 2014 5th wheel. The plastic squirrel cage keeps breaking. Everything in the AC looks fine, the axel coming off the motor doesn't appear bent, nothing is 'hitting' when the AC runs - but the cage broke Oct 2015, Jan 2017 and then again Oct 2017. In Oct, they removed the unit and resocked it down to be sure it wasn't off center. Even so, that cage didn't last even 24 hours so they replaced the cage again this time with a metal one and the unit works fine, but it's loud. The metal cage 'whistles' and is too noisy for nightime (sleep) usage. That isn't acceptable in the summertime in FL, (where I live). The RV Repair place has given up. I don't know what else to do. Any thoughts?

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        Randy Godwin 4 months ago from Southern Georgia

        Tom, either rent or borrow an amp meter to check the compressor. I don't know of anything else which will cause this problem unless there's a bad short somewhere.

        Randy

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        Tom 4 months ago

        The old start capacitor smoke before it when up also. I don't know what would cause this problem I had it plug into house 20 amp breaker and that did not trip

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        Randy Godwin 4 months ago from Southern Georgia

        Tom, it's not rare for a cap to be bad even if new. Did the compressor seem to draw more amps than normal?

        Randy

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        Tom 4 months ago

        A/C did not work, change all capacitors Turned a/c on started fine and was running almost a minute then a noise and smoke blow out the top of the start capacitor. All wires hook up the same way??

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        Randy Godwin 5 months 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

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        Randy Godwin 5 months 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

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        Russell T57 5 months 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.

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        PraireFire 5 months 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

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        Randy Godwin 5 months 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

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        Brian 5 months 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.

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        Randy Godwin 5 months 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

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        Tom 5 months 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?

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        Randy Godwin 6 months 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

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        Mark 6 months 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?

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        Randy Godwin 6 months 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

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        Raymond 6 months 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

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        Randy Godwin 6 months 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

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        Connie 6 months 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?

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        Randy Godwin 6 months ago from Southern Georgia

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

        Randy

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        Chris 6 months 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

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        Raymond 6 months 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

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        Randy Godwin 6 months 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

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        Raymond 6 months 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

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        Randy Godwin 6 months ago from Southern Georgia

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

        Randy

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        Raymond 6 months 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

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        wally kuhns 6 months 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

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        Randy Godwin 6 months ago from Southern Georgia

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

        Randy

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        Randy Godwin 6 months 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 months 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

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