Wide Open Throttle A/C Cut-Off Relay
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2003 Mercury Sable, 2003 Mercury Mountaineer, 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
The Wide Open Throttle A/C Cut-Off (WAC) relay may also be referred to as the A/C clutch relay.
The WAC relay is normally open (normally closed for Aviator). There is no direct electrical connection between A/C switch or Electronic Air Temperature Control (EATC) module and A/C clutch. On some applications, A/C request signal will be sent to PCM through Standard Corporate Protocol (SCP) BUS (+) and BUS (-) circuits. When A/C is requested, PCM will ensure all other A/C related inputs and engine components are operating correctly before grounding WAC relay output (unground for Aviator), causing voltage to be sent to A/C clutch.