Air Conditioning Request

The A/C compressor clutch relay controls the 12-volt source for the A/C clutch. The relay is located in the PDC.
- One side of the relay control coil is supplied with 12 volts when the ignition switch is turned to the "RUN" position.
- The circuit is completed when the other side of the relay coil is grounded by the powertrain control module (PCM).

When the air conditioning or defrost switch is put in the ON position and the low pressure, A/C cycling, and high pressure switches are closed, the PCM receives an A/C input.

After receiving this input, the PCM activates the A/C compressor clutch by grounding the A/C clutch relay.

The PCM adjusts idle air flow through Idle Air Control (IAC) motor -- compensating for increased engine load -- to maintain the scheduled RPM.

The PCM grounds the relay control circuit after receiving an A/C select signal and adjustment of the idle speed has been implemented.