Test U: Both Reversing Lamps Are Inoperative

PINPOINT TEST U: BOTH REVERSING LAMPS ARE INOPERATIVE

Normal Operation
Voltage is supplied from the battery junction box (BJB) fuse 75 (5A) to the coil side of the reversing lamps relay through circuit CBB75 (YE/GY). The reversing lamps relay switch side is supplied voltage by the BJB fuse 33 (20A) through circuit SBB33 (RD). The reversing lamps relay coil ground is controlled by the PCM (automatic transmission, gasoline engine), the transmission control module (TCM) (automatic transmission, diesel engine), or the reversing lamp switch (manual transmission) through circuit CLS28 (BU/WH).

For vehicles with an automatic transmission, when the transmission is in REVERSE (R), the PCM or TCM provide ground for the reversing lamps relay to energize.

For vehicles with a manual transmission, when the transmission is in REVERSE (R), the reversing lamp switch completes the ground path through circuit GD122 (BK) to energize the reversing lamps relay.

When the reversing lamps relay is energized, voltage is routed to the reversing lamps through circuit CLS10 (GN/BN). The reversing lamps share a common ground through circuit GD176 (BK/WH).

- DTC B1910 (Reverse Lamp Control Circuit/Open) - is an on-demand DTC that sets when the PCM (gasoline engine, automatic transmission) or TCM (diesel engine, automatic transmission) detects an open on the reversing lamp relay coil ground control circuit.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Reversing lamps relay
- Reversing lamp switch (manual transmission)
- TCM (automatic transmission, diesel engine)
- PCM (automatic transmission, gasoline engine)

U1-U2:

U3:

U4-U5:

U5-U6:

U7-U10: