Powertrain Control Module

The Powertrain Control Module (PCM) monitors and regulates A/C system. See Fig 1. The Electronic Engine Control (EEC) system, working through A/C relay, disengages A/C clutch under the following conditions: immediately after start-up, wide open throttle, coolant temperature approaching overheating condition, and engine idle RPM approaching stall speed.

Fig 1: Identifying Manual A/C-Heater System Control Components

Courtesy of FORD MOTOR CO.