What is an air compressor relay?
A relay is a switch that sends power to the AC compressor. You might also see the part called a compressor clutch relay or relay switch. The air compressor relay plugs into a fuse box.
The compressor is the AC component that pressurizes the refrigerant (also called coolant), so it can move through the system and create cool air to blow throughout your car’s cabin. If the compressor doesn’t get the power it needs, the whole system struggles to work.
How do I know if my air compressor relay is bad?
Air conditioning problems can be tricky to diagnose since faulty parts may show the same symptoms. If your compressor relay is damaged or broken, look for these common signs:
Air compressor doesn’t switch on: When the AC compressor works, you’ll hear it click, and then the AC blows cool air. If the relay is bad, you won’t hear a click, and the system will blow hot or warm air.
AC works off and on: If the AC works sometimes but not all the time, it’s a sign that the compressor relay needs to be replaced.
AC doesn’t blow cold air: The AC won’t work at all if the relay isn’t sending power to the compressor.
The symptoms of a bad air compressor relay could also point to another problem with your vehicle’s air conditioning system, such as the AC compressor, condensing unit, blower motor, or evaporator. Troubleshooting AC problems can be complicated, so bring the car to a certified AC professional if you’re not sure what’s causing the problem.
How long do air compressor relays last?
Unlike many car parts, compressor relays are measured in cycles of how many times you turn them on and off—not miles or years. A replacement air compressor relay should last for up to 50,000 cycles. Most drivers find that this works out to around ten years’ worth of driving.
Keep in mind: Air compressor relays aren’t inspected during regular car maintenance. If you suspect something is wrong with the compressor relay, ask to get it checked out (along with the rest of your air conditioning system).
Can I replace the AC compressor relay?
If you know your way around your car’s fuse box, you can save on labor costs while doing the car AC repairs yourself. It’s as simple as swapping out switches!
However, if you’re not sure that the air compressor relay is causing the problems with your AC unit, you may want an HVAC professional to make a diagnosis first.