Pinpoint Test X: The Trailer Parking Lamps Are Inoperative

Trailer Lamps

Pinpoint Tests

Pinpoint Test X: The Trailer Parking Lamps Are Inoperative

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

Normal Operation

When the vehicle parking lamps are on, the Smart Junction Box (SJB) provides voltage to the trailer tow connector for the trailer parking lamps.

This pinpoint test is intended to diagnose the following:

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



PINPOINT TEST X: THE TRAILER PARKING 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.

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X1 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR


- Ignition OFF.
- Disconnect the trailer from the vehicle.
- Place the headlamp switch in the PARKING LAMPS ON position.
- For the 4-pin connector, measure the voltage between the trailer tow C439-3, circuit CAT17 (BN), harness side and ground.




- For the 7-pin connector, measure the voltage between the trailer tow connector pin 6, circuit CAT17 (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 SJB fuse 25 (15A) is OK.

If OK for the 4-pin connector, GO to X3.

If OK for the 7-pin connector, GO to X2.

If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number

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X2 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR (7-PIN)


- Disconnect: Trailer Tow C473.
- Measure the voltage between the trailer tow C473-6, circuit CAT17 (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 X3.

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X3 CHECK THE TRAILER TOW PARKING LAMP CIRCUIT FOR AN OPEN


- Place the headlamp switch in the OFF position.
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-13, circuit CAT17 (BN), harness side and the trailer tow C439-3 (4-pin connector) or C473-6 (7-pin connector), circuit CAT17 (BN), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to X4.

No
REPAIR circuit CAT17 (BN) for an open. TEST the system for normal operation.

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X4 CHECK FOR CORRECT SJB OPERATION


- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new SJB. REFER to Body Control Systems. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

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