Normal Operation

WARNING: This page is about a different car, the 2003 Lincoln Aviator. However, it is still accessible from the selected car via links, so may be relevant.

Under normal operation, the Dual Automatic Temperature Control (DATC) module sends a A/C request signal over the communication bus to the PCM. The thermostatic switch and low charge protection switch receive a ground through circuit 570 (BK/WH). The thermostatic switch receives ignition voltage through circuit 1139 (VT/YE). When the thermostatic switch closes, a signal is sent to the PCM through circuit 347 (BK/YE). When the low charge protection switch closes, ground is provided to the high pressure cutoff switch through circuit 439 (TN/LG). When the high pressure cutoff switch closes, a ground signal is received by the PCM through circuit 441 (RD/YE).

The PCM provides a ground for the A/C clutch relay coil through circuit 331 (PK/YE). The A/C clutch relay coil receives ignition voltage through circuit 1139 (VT/YE). Ignition voltage for the A/C clutch relay switch is provided through circuit 1003 (GY/WH). 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 1205 (BK).