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 battery junction box (BJB) supplies constant power to the starter relay on circuit 32 (RD/LB) through fuse F1.105 (30A). When the key is placed in the START position with the vehicle in PARK or NEUTRAL, the transmission range (TR) sensor provides power on circuit 33 (WH/PK) and the powertrain control module (PCM) provides ground on circuit 3405 (GY/RD), activating the starter motor. On police vehicles, the transmission range (TR) sensor provides power on circuit 33 (WH/PK) and ground through circuit 57 (BK), activating the starter motor.