Home Improvement

What Are The Signs Of A Bad Air Conditioner Relay

Relays are small switches that control electricity going to the compressor and motor. An HVAC compressor makes sure to supply cool air to the vents. When the compressor doesn’t receive power, it doesn’t function and the AC doesn’t cool. If your AC is not cooling, the cause of the problems could be a faulty relay. Read below to determine if your AC’s relay switch is bad and consult air conditioning repair services for the replacement.

Inconsistent Cooling

As discussed above that the relay is responsible for allowing electricity to the compressor. If an HVAC relay is malfunctioning, the compressor will get an inconsistent flow of electricity. A compressor is responsible for producing cool air.

So, when the compressor doesn’t receive electricity in a proper manner, the air conditioner’s cooling suffers. You will notice inconsistent cooling where at one moment the AC will be cooling well, but a few minutes later, the AC won’t cool.

It will be different compared to normal cycling off of your AC because the HVAC cycles off when the desired temperature is reached. However, during inconsistent cooling due to an issue with components like the relay, the AC will stop cooling without reaching the desired temperature.

The Compressor Won’t Turn On

Irregular cooling of an AC is common when the relay is failing, but if the relay has stopped working, it won’t send electricity to the compressor and the compressor won’t turn on.

In most air conditioners, you can hear a clicking sound some moments after turning on the AC. The clicking sound is the compressor starting. If you don’t hear the clicking sound, it denotes that the compressor didn’t start. You can check the condenser unit to see if the compressor started. Oftentimes, this is due to a bad relay switch.

The AC Won’t Cool

When the compressor won’t switch on due to a faulty relay, the air conditioner won’t cool. However, there are many reasons for an AC not cooling so you should couple this with other signs to identify that this is due to a malfunctioning relay.

Clicking Or Rattling Noise

In air conditioners and other appliances, when a component weakens and starts lacking in its functionality, it takes more energy to work or start its operation. Due to this, you may hear a rattling noise coming out of the condenser unit. However, keep in mind that, a rattling noise could hint at any other issue as well. For instance, a rattling and thumping noise can be caused by a malfunctioning motor or blower.

Additionally, you may hear a clicking noise when you turn on the AC if a relay switch is faulty. Upon hearing this noise frequently, check the unit and find the cause of the AC problem that may be the relay.

Burning Odor

A faulty relay switch could heat which can lead to a burning smell. Take note a burning smell coming out of the condenser unit denotes an electrical problem. If you notice a burning smell, turn off your air conditioner immediately and consult an expert for checking your HVAC unit.

Avoiding Relay Switch Problems

A switch can go bad due to wear and tear which is normal. You can avoid stuck relay switch with the following tips:

Keep Your Outside Unit Clean

The condenser unit of your AC sits outdoors so it collects a lot of dust and debris daily. If the dust settles inside the unit, many components will start showing problems including a stuck relay switch. Therefore, make sure to regularly clean the outside unit, the condenser coils, and the air filters.

Use The AC In Moderation

When an air conditioner is functioning, it generates heat in the condenser unit which is dissipated with the fan. However, using the AC without giving it some time to cool down can heat up the unit. This can melt the relay material and it will get stuck in one position. So, avoid running the air conditioner when not necessary and turn it off if you’re not at home.


An air conditioner compressor relay switch ensures a cool by running the compressor. Therefore, take note of the above signs and get in touch with HVAC repair services Chantilly for replacing the relay switch.

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