Your air conditioner has a part called a contactor that's responsible for turning the compressor on and off so your AC turns on and cools your home and then shuts down. The contactor is controlled by your thermostat, and if something goes wrong with the contactor, your AC won't operate properly. Your AC may not start, or it may not shut down.

Here's how the contactor works and how an air conditioning repair technician may handle replacing or repairing it when the contactor malfunctions.

The Contactor Supplies Power To The AC Parts

The wiring that provides power to your AC from the electrical box and the wiring from the thermostat enters the side of the condenser and connects to the contactor. The contactor is right behind the service panel, and it's the first part to fire up when the thermostat sends the signal to turn on the compressor.

The contactor then sends power to the capacitor and onto the fan motor and compressor. The contactor acts like a switch that lets electricity flow to the next component in the condenser.

Other Faulty Parts Affect The Contactor

A contactor can fail, but it's also common for other parts to fail and keep the contactor from getting the signal from the thermostat. The air conditioning repair technician has to determine why the contactor isn't pulling in power. They might start by checking the power of the wire going from the control board to the contactor to determine if the power problem is with the inside or outside equipment.

Triggered safety switches, a bad thermostat, a bad power saver switch, or faulty wiring might be keeping power from reaching the contactor, and if these problems are fixed, the contactor might start working again.

A Bad Contactor Can Be Replaced

If the air conditioning repair technician finds that the contactor is the problem, then they may need to replace it. First, they may clean it to make sure debris, dirt, or small insects aren't the problem. The technician can use a multimeter to verify the contactor is bad.

The contactor is a small part that's easy to reach and pull out. It has several wires attached to it, and all of those need to be removed so the old contactor can be pulled out and the new one installed. Once the new contactor is in place and the wires attached, the repair technician can adjust the thermostat to trigger the contactor and make sure it will turn the compressor on and off as it's supposed to.