Throttle Full Open Switch: Description and Operation

WIDE OPEN THROTTLE A/C CUT-OFF (WAC)

The wide open throttle A/C cutoff relay (may be referred to as the A/C clutch relay) is wired normally open (normally closed for Aviator). There is no direct electrical connection between the A/C switch or EATC Module and the A/C clutch. The PCM will receive a signal indicating that A/C is requested (for some applications, this message is sent through the BUS + and BUS - circuits). When A/C is requested, the PCM will check other A/C related inputs that are available (such as ACP (SW), 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 will ground the WAC output (unground for Aviator), closing the relay contacts and sending voltage to the A/C clutch.