Compressor Clutch Relay: Description and Operation

AIR CONDITIONING (A/C) CLUTCH RELAY (A/CCR)

NOTE: The PCM PIDs WAC and wide open throttle air conditioning cutoff fault (WACF) are used to monitor the A/CCR output.

The A/CCR (may be referred to as the wide open throttle A/C cutoff [WAC] relay) is wired normally open. There is no direct electrical connection between the A/C switch or EATC module and the A/C clutch. The PCM receives a signal indicating that A/C is requested (for some applications, this message is sent through the communications network). When A/C is requested, the PCM will check other A/C related inputs that are available (such as ACPSW, ACCS). If these inputs indicate A/C operation is OK, and the engine conditions are OK (such as coolant temperature, engine RPM, throttle position), the PCM grounds the A/CCR output, closing the relay contacts and sending voltage to the A/CC.