Dometic RV Air Conditioner Not Blowing Cold Air (How to Fix)

When you live in a box on wheels, you come to the realization that air conditioning is very important. Staying cool on those hot days means more to you than a great dinner at a fancy restaurant. RV maintenance is vital if you want to remain cool all summer long.

Always check the simple things first. When you notice that your Dometic air conditioner is not blowing cold air, check the power panel. Your problem may be as simple as a tripped or blown fuse. This issue does not take a lot of time to fix.

To learn more about how to fix your Dometic RV air conditioner, just keep reading our article. It is filled with the information you need to know to make sure you stay cool when the weather does not.

Why is My RV AC Not Blowing Cold Air?


There are many issues that can keep your Dometic AC unit from blowing cold air. One has already been mentioned. When the fuse blows or trips, the AC unit does not have the power it needs to keep running.

Another source may be that you or your spouse, etc., have set the thermostat too low. This causes the compressor to overwork and eventually shut down. When this happens, the fan may continue to blow but without the cool air you want.

To fix the first problem, all you need to do is reset or replace the fuse. Then your air conditioner should work just fine. The solution for the second problem is just as easy and as cheap.

To start, you just have to raise the thermostat setting a little higher, maybe 10 degrees higher. Trying to go from, for sake of argument, 90 degree interior temperature to a 70-degree interior temperature is too great a gap for the unit to function properly.

Pressure will build up in the compressor causing it to shut down the cooling unit. But before you reset the thermostat, let the compressor cool down for about 5 to 10 minutes before starting the air conditioner again.

Two other sources could be that the compressor is broken and has stopped producing cold air. Or you have an icing problem which when it takes place, will stop the AC unit from producing any cool air.

To fix the first problem, you need to find out where it is broken and then take the necessary steps to get that part fixed. For the icing issue, it may be a failed ice detector monitor which would need to be replaced as well.

RV AC Blows Cold Then Warm


What causes this to happen is not that difficult to diagnosis. Usually it can be a broken capacitor that stops your AC unit from blowing cold air and lets it blow warm air instead.

Now while some AC repairmen may dismiss this cause if the air conditioner is under 9 or 10 years of age, that doesn’t mean it cannot happen. Usually, a young air conditioner will not have a broken capacitor so soon but when you start feeling warm air coming out of your AC unit, then check the simple solutions first.

That means you need to check your capacitor to make sure it was not defective or that it just simply broke. Another problem that causes this situation is that the compressor in your AC unit has malfunctioned or broke in some way.

The capacitor is easy to fix and you can do it yourself. Just replace it. But if the compressor goes down, you may need a professional AC repairman to handle the repair or replacement.

There is also the possibility that the two fuses on the disconnect may have gone bad. The fan is powered separately on some units so these blown fuses would not affect the fan’s operation.

Just put a meter on the air conditioner to check for the compressor issue and check the fuses to make sure they are working as they should.

RV Air Conditioner Stopped Blowing Cold Air


When your air conditioner unit has stopped working properly, you need to track down all the possible sources for the trouble. There may be more than one. Then, when you find all the possible sources fix them all at the same time.

If you don’t, then the air conditioner will not work right and simply waste a lot of electricity. You may also damage the unit if you do not put it back into peak condition. Saving a few repair dollars may end up costing you more later on.

To prevent this situation from taking place, you should get into the habit of covering your RV air conditioner with a cover when it is not in use. Debris, leaves, dirt, grime and other contaminants can get into your AC unit and cause it to break down.

Even insects, rats, and mice can get inside and ruin your perfectly good Dometic air conditioner. Covering the unit is a way to protect it and the capacitor from potential damage.

Then make sure to do routine and preventive maintenance on your unit and fan. This helps the air conditioner run right and avoid possible problems like the compressor shutting down. “An ounce of prevention is worth a pound of cure” they say so don’t ignore this sage advice when it comes to your RV.

Troubleshooting Your Dometic Air Conditioner

The two main complaints about RV air conditioners are leaks and no cool air. With the former, you can easily spot the problem and tend to it. But with the air conditioner refusing to send out cool air, you may have a more difficult time finding the source.

Here are some steps to take to help you find the source of the problem:

  • Find out if the compressor is working or not - you do this by turning it on and listening for noises and feeling for vibrations. If it isn’t running, then check your thermostat setting or the fuses.
  • Grab a voltmeter - low or no voltage may be the problem. The compressor may be working but it is not getting enough power to cool the air for you. Once you have connected the voltmeter, the display should read 13.4 volts if the power is normal. If the reading is less than that, then you know the source of the problem.
  • Airflow may be the problem - to check and solve this issue look at the air filter. If it is really dirty, then there is not enough airflow for the compressor to cool properly. You will need to clean the filter and any other dirt near the refrigerant section to keep the air flowing smoothly.
  • Check the coils - if these are blocked then they cannot work like they are supposed to. You need to use an air compressor and blow any dirt, or another blockage out of the AC unit. Keep the coils free from blockage and clean and you should be okay.
  • Tears and holes stop cool ai- this usually happens in your duct system so you will need to repair any rips or tears you find. Good duct tape will solve this problem until you can replace the old ducting with new.
  • Look at the registers - if they are dirty or blocked, you won't get the airflow you want and your RV stays a little warmer than necessary. Make sure all the registers are nice and clean as well as free from debris that blocks the airflow.

A Simple Issue That Can Cause Warm Air to Come Out of Your AC


While many people expect to find complicated and difficult problems to solve when their Dometic air conditioner starts to blow warm air, this may not be the case. There is a simple problem that any RV owners do not think about which can cause this problem.

As RVs become more sophisticated and luxurious, they often get air conditioning units that crave power. That is because it takes a lot of power to keep a Class A or even a Class C RV cool for many hours at a time.

The problem with these better upgrades mean that the air conditioners may need more power than can be supplied by different campgrounds or RV parks. Yes, this is a possibility.

A low power supply from the campground will keep your RV air conditioner from blowing cool air, especially when you try to run all the units at the same time. To solve this problem, you may have to shut down one or more AC units or other needed appliances.

Or you may have to move to a new campsite that produces enough power for your units to work properly. At the worst, your RV fuses will trip and you will have to reset them.

More powerful Dometic AC units mean that you need more power to have them work. Campgrounds do not upgrade as fast as RVs do so you need to consider this possibility before you turn into an attractive campsite for the night.

What to Look For in an AC Unit

You may need to replace your old Dometic air conditioner with a new one. Knowing what to look for is very important. You do not want to get a unit that is too small for your RV or doesn‘t have the power you need to keep it cool for hours on end.

Here is a list of things to look for when shopping to replace your old RV air conditioner:

  • BTUs are king - BTU simply means British Thermal unit, and it is the standard most air conditioners are built to. The average air conditioner comes with about 13,500 BTUs and can be written 13.5k BTUs. When you go to hot geographical locations, you will need an air conditioner unit that has more BTUs than the standard if you want t stay cool during your visit.
  • Small profiles may not be good - this is a difficult decision to make as you need a larger profile AC unit in order to keep your RV cool. But the problem is that a larger profile unit may cause drag and wind resistance eating up your fuel supply as you drive. While small profile units are good at cutting drag, etc., they are not good at keeping your RV cool. It is a Catch-22 situation.
  • Combinations save money - if you can get an air conditioner with a heat pump, that should save you a few bucks and lets you use your unit all year round.
  • ​Brand names - these are good to purchase because they are easier to find parts for and easier to fix. Lesser known brands may not be and you may end up replacing those with a top brand name.
  • Installation and maintenance - are these easy to do once you bring the unit to your RV? It is not hard to install a new unit yourself, just follow the instructions. Difficult to install and maintain units should be avoided as they will run your repair costs up.

Some Final Words

When you Dometic air conditioner stops blowing cool air, the causes are not that hard to determine. It may take a little time and patience but that is okay. The causes are usually simple and they are usually simple to fix as well.

A blown fuse just needs to be reset or replaced. A malfunctioning capacitor needs to be replaced as well. The most difficult part to work on would be the compressor which you may not be able to do yourself.

Once you determine the problem, you should be able to have cool air running out of the unit soon. The key to avoiding these situations is to make sure you keep the filters clean, remove blockages, debris, rodents and more.

Also, check the power supply from the campground. It may not be as strong as you would like.

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