Normal Operation

WARNING: This page is about a different car, the 2006 Mercury Grand Marquis and 2006 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

Under normal electronic automatic temperature control (EATC) operation, when A/C is requested, a message is sent over the bus from the EATC module to the powertrain control module (PCM). The PCM receives input from the A/C cycling switch through circuit 883 (PK/LB). Voltage is provided to the A/C cycling switch through circuit 348 (RD/VT).

Under normal manual climate control operation, when A/C is requested the function selector switch sends voltage to the A/C cycling switch through circuit 348 (RD/VT). The PCM receives input from the A/C cycling switch through circuit 883 (PK/LB). Voltage is supplied to the function selector switch through circuit 1040 (RD/BK).

The PCM provides a ground for the A/C clutch relay coil through circuit 73 (OG/LB). The A/C clutch relay coil receives ignition voltage through circuit 391 (RD/YE). Ignition voltage for the A/C clutch relay switch is provided through circuit 1810 (LG/OG). When the relay is activated, ignition voltage is supplied to the A/C clutch solenoid through circuit 321 (GY/WH). Ground is supplied for the A/C clutch through circuit 57 (BK).