Pinpoint Test V: The Trailer Reversing Lamps Are Inoperative

Trailer Lamps

Pinpoint Test V: The Trailer Reversing Lamps Are Inoperative

The Battery Junction Box (BJB) fuse 58 (15A) receives voltage when the vehicle reversing lamps are illuminated. The voltage is then routed to the trailer tow connector.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- Trailer tow connector

- Trailer

PINPOINT TEST V : THE TRAILER REVERSING LAMPS ARE INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Before beginning diagnostics, visually inspect the trailer tow connector for signs of corrosion or damage. Repair or install a new trailer tow connector as required.

V1 CHECK FOR VOLTAGE AT THE TRAILER SIDE OF THE TRAILER TOW CONNECTOR

- Apply the parking brake.

- Ignition ON.

- Select REVERSE.

- Measure the voltage between the trailer tow connector reversing lamp voltage supply pin, circuit CAT03 (GY/BN), component side and ground.





Is the voltage greater than 10 volts?

Yes
The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.

No
VERIFY the BJB (Battery Junction Box) fuse 58 (15A) is OK. If OK, GO to V2. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.

V2 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR ON THE VEHICLE HARNESS

- Select PARK.

- Ignition OFF.

- Disconnect: Trailer Tow C4099.

- Ignition ON.

- Select REVERSE.

- Measure the voltage between the trailer tow C4099-7, circuit CAT03 (GY/BN), harness side and ground.





Is the voltage greater than 10 volts?

Yes
INSTALL a new trailer tow connector. TEST the system for normal operation.

No
GO to V3.

V3 CHECK FOR VOLTAGE TO THE TRAILER TOW REVERSING LAMP FUSE

- Measure the voltage between the BJB (Battery Junction Box) fuse 58 (15A), circuit CLS28 (BU/WH), input side and ground.





Is the voltage greater than 10 volts?

Yes
REPAIR circuit CAT03 (GY/BN) for an open. TEST the system for normal operation.

No
REPAIR circuit CLS28 (BU/WH) for an open. TEST the system for normal operation.