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RV Air Conditioner Clicks But Won’t Turn On – What to Do

If you’ve gone to turn on your RV’s air conditioner and found it making noises, you’re undoubtedly worried. The only sound you’re likely trying to hear from it is the whooshing of cool air being pumped into your vehicle. If you’re out on the road and hearing your RV AC making a clicking sound, but not turning on, you’ll need to find out why. 

If your RV’s AC clicks but doesn’t turn on, it could be an issue of the power system. If a breaker is tripped, the AC won’t be able to activate. There are also possible wiring issues, a faulty motor or compressor, or issues with the thermostat. 

RV Air Conditioner Clicks But Won’t Turn On 

Power System Fault

The first place you’ll want to check is your RV’s power systems. Take a look at the 12V panel and circuit breakers. If you see that a fuse is blown on the 12V panel, it may be time tp replace it. 

More easily fixed, the problem could also be if a breaker is tripped. If that’s the case, you might just have to flip the breaker and get things going again. Either way, replacing the fuse or flipping the breaker, might help to get your AC back in shape. 

This can happen if the power supply at the campground you’re parked at isn’t strong enough for the AC. However, most modern campgrounds use a 50A service, which helps most ACs. If you’re at an older site with 15A power poles, you might run into this issue. 

Regardless, even at a newer camp, you should still take a look at the breakers and fuses. Sometimes other things can trip a breaker or blow a fuse, and it’s worth checking out. 

If that doesn’t solve the issue, you may have to verify that other parts of your RV are working correctly. 

Wiring Issues 

Head to where the wires head from the AC to the power outlet. This is where some of your problems could arise, causing it to click without turning on. If the wires are frayed or dead, that’s the root of your issue. 

If you see this, call a professional HVAC mechanic. Dealing with wires like this could be potentially dangerous for average RV DIYers. Even if you’re out on the road in the middle of nowhere, find somewhere cool to stay until you can get it looked at professionally. 

Faulty Compressor 

When the motor or compressor aren’t working, the entire system is going to shut down. Check the motor to see if it is trying to run when you go to turn the RV AC on. If it’s not kicking to life, that’s likely your issue. 

Relay Issues 

It’s normal to hear a clicking sound when your AC adjusts its settlings, or automatically calls for cool air. What makes this noise is a part called the relay. The relay opens and closes, turning your AC on and off. 

The thermostat is important for your AC’s health. If you touch the wires of the thermostat together and the AC turns on, there’s likely a fault. You can use a multimeter to check the voltage of a wall-mounted  thermostat system. 

Wall mounted thermostats shouldn’t make that loud of a sound. If the clicking happens but the AC isn’t turning on, your issue could be the thermostat. 

Check the AC system’s control board if the thermostat and capacitors seem to be functioning. The control board gets signals from the thermostat before sending electrical power to different parts of the AC. This tells them to turn on and off. 

As with any electrical part, it can encounter bugs and glitches. A glitch in the electrical control could cause the relay to timeout. When that happens, the relay will fail, causing the click. 

If the thermostat is defective, it’s not too hard to replace. On the other hand, the AC unit’s control board is much more complicated to swap out. 

Dirty Components 

A less extreme problem, and one that is more easily remedied, sometimes things just get dirty. Buildup of dirt and debris in the filters, evaporators, and the condensers is one of the top reasons AC systems fail. Regularly servicing and cleaning your parts will keep everything running in good shape.

If your AC has filters, make sure you’re on top of changing or cleaning them on the recommended schedule. 

Low Refrigerant 

Refrigerant is, as the name implies, what keeps your AC running nice and cool. If that runs low, your AC won’t work correctly. Even if it turns on, it’s more than likely that it won’t supply cool air. 

If your AC uses R410A or R134A, it will be easier to refill. If it uses any of the R22 types, seek a professional to see to the refill. 

Faulty Capacitor 

RV air conditioners will have two capacitors. One will be a motor run, while the other is a motor start capacitor. Motor run capacitors are used in the blower fan circuit, and the motor start is in the compressor. 

Each serves a different purpose, and each can go wrong in different ways. If you’re hearing a clicking or humming noise, it could be a fault of the capacitor. 

The clicking noise, usually followed by a soft humming or buzzing, indicates that the motor is trying to turn on, but isn’t getting any help from the capacitor. 

You can run a test on the capacitor to see if it is not working correctly. Please only undertake this test if you’re confident in your ability to do so. Working with electrical components such as this can be very dangerous. 

Testing Your RV AC Capacitor 

  1. Switch off the AC circuit breaker to the RV. If you’re having trouble finding it, check in the electrical load center on your RV. If you’re connected to shore power, remove the connection. 
  2. Head up to the roof of your RV and unscrew the protective housing around the air conditioner unit. You’ll need a Phillips head screwdriver to remove all of the screws around the housing. 
  3. Locate each of the enclosures that house the capacitors. On most models, the enclosure is on the top right corner of the AC’s assembly. It will likely be facing the front of the RV. If you’re unsure, there may be a wiring diagram that you can reference. 
  4. Inspect the enclosure to find the capacitors themselves. The motor run might be silver and oval-shaped, usually 2-3 inches long. 
  5. Now that you’ve found the capacitors, discharge both of them by shorting the electrical terminals located atop the capacitor. 
  6. Find the electrical leads that run from inside the motor run capacitor. Make a note of what terminal all of the wires are connected to.
  7. Take a measurement of the capacitance of the motor run capacitor. Use a multimeter switched to capacitance mode. Place the red, positive lead on a positive terminal on the capacitor. Likewise, apply the black, negative lead on the corresponding terminal. 
  8. Compare the reading you get from the multimeter to what the value on the capacitor states. If it’s not in the right range, you know your capacitor is the reason your RV air conditioner clicks but doesn’t turn on. You will need to replace it in this case. 
  9. Repeat these steps for the motor start capacitor. 

Replacing your capacitor could make your AC function properly again. Thankfully, replacing the capacitor is less expensive than swapping out the entire unit. 

Other signs of a bad capacitor include the bottom or top of the capacitor bulging out in an unusual way. Another sign is any visible, gooey discharge on the capacitor. 

Conclusion 

When you go to turn the AC on in your RV, you’re expecting one thing: cold air. However, if your RV air conditioner clicks but doesn’t turn on, you know something has gone wrong. Of the things that could cause this phenomena, culprits include a failed capacitor, dirty components, or low refrigerant. 

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