Compressor Clutch Relay: Description and Operation

The Wide Open Throttle A/C Cutoff (WAC) output from by the Powertrain Control Module (PCM) controls A/C clutch operation. When A/C is requested to the PCM through the Air Conditioning Cycle Switch (ACCS) input, the PCM adjusts idle speed as necessary and ungrounds the WAC output, which signals to the Constant Control Relay Module (CCRM) that the A/C clutch may be activated. The CCRM then supplies voltage to the A/C clutch circuit, activating the A/C clutch. During A/C operation, if the PCM determines that A/C clutch operation is not desireable, the WAC output is grounded (activated) and the CCRM turns OFF the A/C clutch. Under normal circumstances with the A/C OFF, the PCM grounds the WAC output.