A/C Clutch Relay Circuit

NAME OF CODE:
A/C Clutch Relay Circuit

WHEN MONITORED:
With the ignition key ON and battery voltage greater than 10 volts.

SET CONDITION:
An open or shorted condition is detected in the A/C clutch relay control circuit.

THEORY OF OPERATION:
The A/C compressor clutch relay controls the 12-volt source for the A/C clutch. If the vehicle is equipped with a power distribution center (PDC), the relay will be 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 A/C is requested, the PCM will adjust the idle speed to accommodate the A/C compressor load on the engine. The PCM grounds the relay control circuit after the PCM receives an A/C select signal and adjustment of the idle speed has been implemented.

POSSIBLE CAUSES:
- Relay coil open or shorted
- Fused ignition switch output circuit open
- Compressor clutch relay control circuit open or shorted
- Inoperative circuit driver in powertrain control module