Troubleshooting A T-One Wiring Harness On a 2005 Jeep Liberty

Expert Reply:

It sounds like you have a dead short on the tail light circuit that is contacting the left blinker circuit in the converter box on your Liberty. I would use a circuit tester, item # 3808 if needed, and check the wiring going into the converter box on the T-One wiring harness, after reconnecting the harness.

You should have 5 wires to test (see video). The red wire should have power when the brake pedal is depressed. The green wire should have intermittent power when the right turn signal is activated. The brown wire should have power when the tail lights are activated. The yellow wire should have intermittent power when the left turn signal is activated. Finally you should have a ground wire that is connected to a clean, paint and rust free surface.

If you have a problem with the wiring before the converter box then one of the connectors on the wiring harness is shorting, since the Jeep is working properly with the harness removed.

If the problem is after the wires go into the converter box then the converter box is damaged.

In either case you will need to replace the wiring harness. I would also closely check the wiring on any trailer that I have recently towed, for a short or ground problem. This is usually the cause for the converter or wiring harness to go bad.

expert reply by: Bob G