Pinpoint Test

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.

CHECK THE RELAY GROUND CIRCUIT FOR AN OPEN

Ignition OFF.
Disconnect: Trailer Tow Parking Lamp Relay.

Measure:

BJB			BJB

Trailer Tow Parking Lamp Relay			Trailer Tow Parking Lamp Relay
Pin	Circuit	Measurement / Action	Pin	Circuit
3	SBB84 (GN/RD)		1	GD120 (BK/GN)

Is the voltage greater than 11 volts?

Yes: GO to 2 .
No: REPAIR the circuit.

CHECK THE TRAILER TOW GROUND CIRCUIT FOR CONTINUITY TO GROUND

For the 4-pin connector, measure:

Trailer Tow			Ground

C439			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
4	GD351 (BK/GN)		-	Ground

For the 7-pin connector, measure:

Trailer Tow Connector			Ground

Trailer Tow Connector			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
2	GD351 (BK/GN)		-	Ground

Is the resistance less than 3 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 trailer tow connector ground circuit for an open.
For the 7-pin connector, GO to 3 .

CHECK THE TRAILER TOW GROUND CIRCUIT FOR AN OPEN

Disconnect: Trailer Tow Connector.

Measure:

Trailer Tow			Ground

C4099			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
2	GD351 (BK/GN)		-	Ground

Is the resistance less than 3 ohms?

Yes: INSTALL a new trailer tow connector. TEST the system for normal operation.
No: REPAIR the circuit.