Normal Operation

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. 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 27 (10A) (non-hybrid) or fuse 28 (15A) (hybrid) to the coil side of the reversing lamps relay. The reversing lamps relay switch side is supplied voltage by the BJB fuse 35 (10A). The reversing lamps relay coil ground is controlled by the PCM (automatic transaxle) or the reversing lamp switch (manual transaxle).

For vehicles with an automatic transaxle, when the transaxle is in REVERSE (R), the PCM provides ground to energize the reversing lamps relay.

For vehicles with a manual transaxle, when the transaxle is in REVERSE (R), the reversing lamps switch completes the path to ground to energize the reversing lamps relay.

When the reversing lamps relay is energized, voltage is routed to the reversing lamps. The reversing lamps share a common ground.

DTC P1910 (Reverse Lamp Control Circuit/Open) - sets when the PCM detects no voltage from the reversing lamps 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 (manual transaxle)
PCM (automatic transaxle)