Pinpoint Test X: All The Trailer Lamps Are Inoperative

Trailer Lamps

Pinpoint Test X: All The Trailer Lamps Are Inoperative

Normal Operation

The trailer tow connector receives ground through a dedicated ground circuit. This circuit is the shared ground for all of the trailer lamps.

All of the trailer lamp relays share a common ground.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Trailer tow connector

- Trailer

PINPOINT TEST X : 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 mounted on the bumper for signs of corrosion or damage. Repair or install a new trailer tow connector as required.
NOTE:
Failure to disconnect the battery when instructed results in false resistance readings.

X1 CHECK THE RELAY GROUND CIRCUIT FOR AN OPEN

- Ignition OFF.

- Disconnect: Trailer Tow Parking Lamp Relay.

- Measure the voltage between the trailer tow parking lamp relay pin 3, circuit SBB67 (BU/RD), BJB (Battery Junction Box) face side and the trailer tow parking lamp relay pin 2, circuit GD123 (BK/GY), BJB (Battery Junction Box) face side.






Is the voltage greater than 10 volts?

Yes
GO to X2.
No
REPAIR circuit GD123 (BK/GY) for an open. TEST the system for normal operation

X2 CHECK THE TRAILER TOW GROUND CIRCUIT FOR CONTINUITY TO GROUND

- Disconnect: Negative Battery Cable.

- For the 4-pin connector, measure the resistance between the trailer tow C439B-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 circuit RAT08 (WH) for an open. TEST the system for normal operation.

For the 7-pin connector, GO to X3.

X3 CHECK THE TRAILER TOW GROUND CIRCUIT FOR AN OPEN

- Disconnect: Trailer Tow C439A.

- Measure the resistance between the trailer tow C439A-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.