Close this search box.

Why Is My RV Air Conditioner Not Cooling?

As with all things in life, RV air conditioners (AC) are bound to need a little bit of love and attention every once in a while. If your RV’s AC isn’t cooling properly, there are a few things that could be causing it.

First, your AC unit could just be old. Beyond that, there could be built up grime and plant material blocking its air filters – or it could simply be too hot for a single AC unit to do the job properly. Here’s how to figure out what’s wrong.

Diagnosing The Problem

First things first, we’ve gotta figure out what’s going on with your AC unit. We all love camping (that’s why you’re here, right?) but nobody wants to be in a metal sauna when they’re doing it. Not only is it uncomfortable, it’s outright dangerous to both you and any fuzzy friends you brought along for the adventure.

So how do you figure out what’s causing the problem?

First Steps:

Let’s begin with the easy stuff, yeah? After all, nobody wants to start digging in their machine’s guts unless they absolutely have to. So where should you start?

  1. Check the thermostat – I know this seems like common sense, but you’d be surprised what being too hot can do to your basic thinking processes. If you’re stuck in an uncomfortably hot RV, this is the first place to start. Make sure it’s set to the right temperature, check the batteries, and check the temperature sensor – you may need to replace it.
  2. Visual inspection Pop open the shroud and look around the unit. Do you see frost, dirt, or feel unexpected heat coming from any parts of the machine? If so, these are signs that you may need to move down to the tips below.
  3. Inspect your fan – If your AC is only functioning at certain speeds or temperatures, it’s possible the fan is dying or dirty. Check your fans and replace any clearly-aged ones, then test the AC
  1. Check the freon levels – Freon is vital to your AC’s daily operation. If the freon levels are low, you’ll notice ice or frost buildups on the unit. This means it’s time to re-up on your freon. And don’t skimp – this is absolutely integral to the functioning of your AC unit. As with most things, if you buy cheap, you can expect cheap performance.

Bigger Projects:

  1. Turn it off – As with any electronics, make sure your AC (and RV) are completely off before trying to dig into the machine. It doesn’t matter how hot it is – it’s not worth an electrocution.
  2. Filters – Okay, now that it’s all off and safe, let’s take a look at the filters in your AC unit. If they’re exceptionally grimy and old, that’s likely a good place to start. Replace your filter (they’re not too expensive), boot up the AC, and see what happens.
  3. Coils – If that didn’t work, it’s time to check out the coils – both condenser and evaporator coils. Cleaning (or worst case, replacing them) should solve the problem if the filter aforementioned steps didn’t.
  4. Compressor – If freon replacements and cleaning the interior didn’t fix the problem, you may need to replace your compressor. While this technically is something that you can do yourself, if you (like myself) aren’t a mechanical savante, it’s probably best to take it to a professional.
  5. Capacitor – These can go bad for a variety of reasons, but it generally boils down to age and disuse. If your AC hums on startup, blows a fuse or breaker, or only blows hot air, it’s likely your capacitor has gone out and needs replacement. Another sign would be smoke coming from the unit, but that’s a pretty obvious sign something is very wrong.

How Do I Test My Capacitor?

All you need to do to test it is use a standard multimeter and see if the value displayed slowly drops over time. If not, you’ve got a bum capacitor. Luckily this is pretty easy as long as you get the right voltage for your new capacitor – so be sure to take note.

Replacing A Capacitor

First things first – a capacitor’s job is to store electricity. Remember when I said to turn everything off? Yeah, same thing here, except you should never touch it with your bare hands. Use rubber or other charge-dissipating materials to handle your capacitor.

After this, do your due diligence on planning and remembering where everything goes. Using wire labels or even a strip of tape can go a long way here (or, you know, take a photo). Once you know where it all goes, carefully remove the capacitor and discharge it by attaching both ends of the terminal to a piece of conductive metal (so no stainless steel, please).

After this, it’s just a matter of putting the new capacitor in, and following the notes that you definitely took on where it all goes (I’m looking at you, Mike – if you took notes, things would be so much easier).

How To Know If I Need To Hire A Professional?

This is subjective. If you’re extremely mechanically inclined, then most things should be doable. (Assuming you do your research first.) If you find replacing a fan or bad thermostat to be difficult, that’s where to stop. Please don’t touch the capacitor or try to fully rebuild an AC motor. It is potentially dangerous, and also wildly frustrating. So just take it to a professional – that’s what they’re there for, after all.

Final Thoughts

There’s a lot that can cause an RV AC unit to fail. By following the above steps in order, you should be able to find the culprit without too much unnecessary work. Remember – work smarter, not harder.

Scroll to Top