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 operation, the electronic automatic temperature control (EATC) module is grounded through circuit 57 (BK). The EATC module receives battery voltage through circuit 1566 (RD/YE) and ignition voltage through circuit 1812 (BN/WH).