Troubleshooting Tow Ready Trailer Wiring Harness # 118336 on 2002 Acura

Question:

I am getting no voltage from the brown wire right brake / turn

asked by: Brendan

Expert Reply:

The brown wire exiting the output side of the converter carries the signal for the running lights, so it would not show any current while the right turn signal is activated, or the brake pedal is pressed. The right turn/brake is carried by the green wire, left turn/brake by the yellow wire, running lights by the brown wire and the white wire grounds the converter to the vehicle.

To troubleshoot your # 118336 wiring harness, use a circuit tester like part # PTW2993. Ground the tester to the ground pin on the connector, while having a helper activate the running lights. Use the tester to probe the socket of the trailer connector fed by the brown wire. The tester should light up. Then, activate the left turn, and test the socket fed by the yellow wire. The tester should blink and should also light up when the brake pedal is pressed. Then activate the right turn signal and test the socket fed by the green wire. The tester should blink should light up when the brake pedal is pressed.

If any one of the circuits does not show current while its function is activated, test the wires on the input side of the converter (see photo). Just like you did above, activate the right turn signal and test the green wire, but this time on the input side of the converter. Do the same for the left turn, brake lamp, and running lamps. If you have signal going into the converter on the input side but not exiting it on the output side, the converter is shorted out and should be replaced.

Keep in mind, before replacing the converter, you will need to check the wiring on the trailer, looking for the wiring problem that caused the converter to short out. Look for a damaged or corroded wiring connector on the trailer and trace each circuit back to its lamp. Look for pinched or broken wires, or loose connections. Examine the wire insulation for cracks or worn spots that would allow the copper conductor to short out to the trailer frame.

I have linked you to some trailer wiring FAQ articles that you should find helpful.

expert reply by: Mike L