Pinpoint Test W: All The Trailer Lamps Are Inoperative

Trailer Lamps

Pinpoint Tests

Pinpoint Test W: All the Trailer Lamps Are Inoperative

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

Normal Operation

Ground for all the trailer lamps is provided through a single ground circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Trailer tow connector
- Trailer



PINPOINT TEST W: 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: 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.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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W1 CHECK GROUND CIRCUIT FOR AN OPEN TO THE TRAILER TOW CONNECTOR


- Disconnect the trailer from the vehicle.
- Disconnect: Negative Battery Cable.
- For the 4-pin connector, measure the resistance between the trailer tow C439-4, circuit RAT08 (WH), harness side and ground.




- For the 7-pin connector, measure the resistance between the trailer tow connector pin 2, circuit RAT08 (WH), component 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
For the 4-pin connector, REPAIR the circuit. TEST the system for normal operation.

For the 7-pin connector, GO to W2.

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W2 CHECK THE GROUND CIRCUIT FOR AN OPEN


- Disconnect: Trailer Tow C473.
- Measure the resistance between the trailer tow C473-2, circuit RAT08 (WH), harness side and ground.




- Is the resistance less than 5 ohms?

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

No
REPAIR circuit RAT08 (WH) for an open. TEST the system for normal operation.

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