Normal Operation

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

Voltage is supplied from the Battery Junction Box (BJB) fuse 47 (10A) to the coil and switched sides of the reversing lamps relay. When the reversing lamps relay is energized, voltage is routed to the reversing lamps.

Automatic Transaxle

The PCM (2.5L or 3.0L engines) or the Transmission Control Module (TCM) (3.5L engine) monitors the transaxle gear status. When the PCM detects the transaxle in REVERSE (R), the PCM or TCM provides ground for the reversing lamps relay coil.

Manual Transaxle

The reversing lamp switch controls the coil ground side of the reversing lamps relay. When the transaxle is in REVERSE (R), the reversing lamp switch contacts close, completing the path to ground for the reversing lamps relay coil.

DTC P1910 (Reverse Lamp Control Circuit/Open) - sets when the PCM detects no voltage on the reversing lamp relay coil ground control circuit (if the coil voltage supply circuit or the coil ground control circuit is open).

This pinpoint test is intended to diagnose the following:

Fuse
Wiring, terminals or connectors
Reversing lamps relay
Reversing lamp switch
PCM
TCM