Skip to Content

Air Conditioning Compressor Not Working? Here’s What to Do…

If your air conditioning is not turning on or failing to cool your home properly, there’s a good chance that it’s because the compressor in your system is faulty. The good news is that compressors can be fixed. However, if your cooling system is more than 15 years old, you may want to consider replacing the whole unit instead of fixing the compressor.

For those homeowners that are inexperienced with air conditioners and how they work, an air conditioning compressor is an essential part of your cooling system. Without it, your system simply won’t produce cool air for your home.

The compressor begins by taking gaseous refrigerant that’s both cool in temperature and low in pressure and compresses it until the temperature of the refrigerant is hot and has a higher pressure. Once the refrigerant is both hot and higher in pressure, it’s then pushed through the condenser and transformed into cool air. This is why the compressor is so important.

Examine your unit for power

Before you start diagnosing your air conditioning system, it’s important to check to see if your unit is getting adequate power. Start by inspecting your fuse box to make sure that a fuse has not blown or a breaker didn’t get accidentally tripped. Once you’ve ensured that a lack of power is not the issue, you can then move on.

It’s important to note that if your home’s fuses and breakers are continuously having problems, it’s best to call a professional to take a look and fix the problem. Having your air conditioner’s compressor turn on and off repeatedly could cause damage to it.

Check the thermostat

In addition to inspecting your home’s fuses and breaker box, you’ll also want to check to make sure that your thermostat has not been turned to the “Hot” or “Off” position. While inspecting your thermostat, also check to make sure the device is not stuck or broken. If your thermostat is broken, you can purchase a replacement part at most home improvement stores.

Buildup of dirt and debris

Another common cause of your air conditioning compressor not working could be due to a homeowner neglecting to clean their system. Overtime, dirt, debris and other filth can clog up your filter, block up your register and completely shut down your system. If you think this may be the problem, get inside and inspect the system. If you notice that the filter is dirty, you should replace this as soon as possible. Filters are very inexpensive and easy to replace.

Refrigerant pressure safety

Most air conditioner systems on the market today have a safety cut-out switch that will turn the system off when the refrigerant pressure is too high or too low. To check the pressure in your unit, you can invest in a pressure gauge from your local home improvement store. If your system’s pressure is low, you will need to charge your refrigerant pressure. Unless you have experience and the right tools, it’s best to hire a professional to complete this for you.


If the voltage being delivered is much to low, then this could be one of the reasons why your central air compressor is not running. If there isn’t enough power getting to your unit, it’s just not going to work properly. Most home improvement stores sell voltage testers. If you find that there is a voltage shortage, it’s best to call a professional to ensure your central air compressor will receive the voltage necessary to run smoothly.

Faulty wires

Another part of your cooling system that you want to make sure you check is the electrical wiring on the inside of the unit. Look for disconnected, burnt and shorted wires around and connected to the compressor. If you happen to see some disconnected wires, find your user’s manual and examine the diagrams. Most of the wires connected to the compressor are not too hard to reconnect.

On the other hand, if you see some burnt or shorted wires, it’s best to call a professional unless you are experienced in this area. Above all, if you do decide to repair on the wiring, double-check to make sure you have shut down the system’s power source before working on it.

Faulty capacitor and starter relays

The capacitor and starter relays are extremely important parts of your system and can definitely be a factor as to why AC compressor not turning on. These parts provide a quick jolt of power which starts the compressor and runs it as well. When these parts are broken, the compressor simply wont run properly or run at all. However, the good news is, repairing the capacitor and the starter relays is an extremely inexpensive job.

To test the capacitor and starter relays to see if they’re damaged, you’ll have to visually inspect them. While visually inspecting them, look to see if the skin on the top of them are blown out. This is your best indication that the capacitor and starter relays need to bee replaced.

Faulty Valves

It’s also important to check to see if any of the valves on the inside of your system are faulty. Valves that are broke, cracked or damaged can leak refrigerant. Once the refrigerant level in your system becomes too low, like mentioned earlier, your system’s compressor will start to work poorly and can even result in the AC condenser not working.

A dead compressor

If after inspecting and testing everything mentioned above your air conditioning compressor is still not working, then it’s a very likely chance that the compressor is dead.

In this situation, you can either replace just the compressor or the complete unit. However, a good rule of thumb to go by is if the price to replace the compressor is more than half of the price of a new unit, you might as well just shop around and invest in a new unit. However, if your system is fairly new, and the price to fix the compressor is not too expensive, then you might just want to replace it.

Michael Joseph