Air Conditioner (A/C) Relay

Air Conditioner (A/C) Relay

The air conditioner (A/C) relay is an electrically-operated switch that supplies power to the air conditioning compressor clutch and air conditioning compressor when you press on the button marked with “A/C” on your dashboard.

Signs of a failing air conditioner (A/C) relay

Your A/C works intermittently

A failing A/C relay can work randomly as it ages and its contacts wear out. That’s why you may need to turn on and off the A/C button a couple of times to engage the A/C compressor.

Only warm air comes from the vents

This can be a sign of a faulty A/C relay, especially if you do not hear a click when turning on the A/C button. This means the A/C relay does not send signals to the air compressor.

Blinking A/C light

You may notice a blinking A/C light if there are any A/C system problems.

Air conditioner (A/C) relay troubleshooting and replacement

  • In most cases, replacing an A/C relay is an easy job to do. However, the A/C relay should be properly diagnosed before replacing it to avoid unnecessary expenses.
  • If you hear a click when pushing on the A/C button, but the A/C doesn’t receive power, this means your A/C relay receives electrical current but doesn’t distribute it to the compressor. The relay must be properly diagnosed in this case.
  • The A/C relay is not the only part that controls power supply to the compressor. You may have another faulty component in the air compressor circuit that interrupts signals to the A/C.
  • Depending on your vehicle, you may not have an A/C relay. The A/C can be operated by the engine control module by means of a compressor control valve.