Pinpoint Test AE: All The Trailer Lamps Are Inoperative

Trailer Lamps

Pinpoint Test AE: All The Trailer Lamps Are Inoperative

Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information Electrical Diagrams.

Normal Operation

All of the trailer tow relay coils share a common ground circuit. The trailer tow connector has a single ground circuit for all of the trailer lamps.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Trailer

PINPOINT TEST AE : ALL THE TRAILER 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: Failure to disconnect the battery when instructed results in false resistance readings.

AE1 CHECK THE TRAILER TOW RELAY GROUND CIRCUIT FOR AN OPEN

- Measure the voltage between the trailer tow parking lamp relay pin 3, circuit SBB84 (GN/RD), BJB (Battery Junction Box) face side and the trailer tow parking lamp relay pin 2, circuit GD120 (BK/GN), BJB (Battery Junction Box) face side.






Is the voltage greater than 10 volts?

Yes
GO to AE2.

No
REPAIR the circuit. TEST the system for normal operation.

AE2 CHECK THE TRAILER TOW GROUND CIRCUIT FOR AN OPEN

- Disconnect: Negative Battery Cable.

- Disconnect: Trailer Tow C439.

- Measure the resistance between the trailer tow C439-4, circuit RAT08 (WH), harness side and ground.






Is the resistance less than 5 ohms?

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

No
REPAIR circuit RAT08 (WH) or circuit GD149 (BK/GY) for an open. TEST the system for normal operation.