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.
When the ignition switch is in the RUN position, voltage is provided to the digital transmission range (TR) sensor from the central junction box (CJB) through circuit 1789 (VT/WH). When the transmission is placed in REVERSE, the digital TR sensor routes voltage to the reversing lamps through circuit 140 (BK/PK).