A/C Clutch Relay Circuit

WHEN MONITORED
With the ignition 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.

- 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 adjusts the idle speed to compensate for the A/C compressor load on the engine.

The PCM grounds the relay control circuit after the PCM receives an A/C select signal over the CCD bus 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 PCM