Pinpoint Test AB: The Trailer Lamps Are On Continuously

Trailer Lamps

Pinpoint Tests

Pinpoint Test AB: The Trailer Lamps Are On Continuously

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

Normal Operation

Voltage to the trailer tow lamps is controlled by the Smart Junction Box (SJB). Circuits CAT06 (YE) and CAT09 (GN) supply voltage to the trailer tow LH and RH stoplamps.

The trailer tow parking lamps share the same voltage supply with the vehicle parking lamps.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Trailer
- SJB



PINPOINT TEST AB: THE TRAILER LAMPS ARE ON CONTINUOUSLY

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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AB1 CHECK FOR VOLTAGE AT THE TRAILER TOW CONNECTOR


- Ignition OFF.
- Disconnect the trailer from the vehicle.
- Ignition ON.
- Measure the voltage between the trailer tow connector, harness side and ground as follows:









- Is any voltage present?

Yes
GO to AB2.

No
The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.

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AB2 CHECK THE SJB


- Ignition OFF.
- Disconnect: SJB C2280a.
- Ignition ON.
- Measure the voltage between the trailer tow connector, harness side and ground as follows:









- Is any voltage present?

Yes
REPAIR the circuit in question. TEST the system for normal operation.

No
GO to AB3.

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AB3 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. CLEAR any DTCs. REPEAT the self-test.

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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