A/C Clutch Relay Circuit

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 air control motor 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.
- Connector terminals.
- Connector wires.