Test U: The Reversing Lamps Are Inoperative

PINPOINT TEST U: THE REVERSING LAMPS ARE INOPERATIVE

Normal Operation
Voltage is supplied from the battery junction box (BJB) fuse 33 (20A) to the switched side of the reversing lamps relay. The reversing lamps relay coil power is supplied by the transmission control module (TCM) (also called a main control valve body for Expedition and a mechatronic assembly for Navigator) through circuit CAT03 (GY/BN). The reversing lamps relay coil ground is controlled by the TCM through circuit RET24 (BN/BU). When the reversing lamps relay is energized, voltage is routed to the reversing lamps through circuit CLS10 (GN/BN).

- DTC P1910 (Reverse Lamp Control Circuit/Open) - sets when the TCM detects an open from the reversing lamps relay coil voltage supply circuit.
- DTC P1911 (Reverse Lamp Control Circuit Low) - sets when the TCM detects a short to ground from the reversing lamps relay coil voltage supply circuit.
- DTC P1912 (Reverse Lamp Control Circuit High) - sets when the TCM detects a short to voltage from the reversing lamps relay coil voltage supply circuit.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Reversing lamps relay
- BJB
- TCM

U1:

U2:

U3-U4:

U4-U5:

U5-U6:

U6 Continued:

U6-U7: