Air Conditioning (A/C) Clutch Relay
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The A/C clutch relay (may be referred to as the wide open throttle A/C cutoff relay) is wired normally open. There is no direct electrical connection between the A/C switch or electronic automatic temperature control (EATC) module and the A/C clutch. The PCM receives a signal indicating that A/C is requested. When A/C is requested, the PCM checks other A/C related inputs that are available. If these inputs indicate A/C operation is OK, and the engine conditions are OK (coolant temperature, engine RPM, throttle position), the PCM grounds the WAC output, closing the relay contacts and sending voltage to the A/C clutch.