Troubleshooting Wiring For Short Circuit Or Bad Wiring Harness Module on 7-Way Trailer Connector

Updated 08/21/2017 | Published 08/19/2017

Question:

Im getting power to the right side but not the left.i even disconnected the plug from the wire harness. Can a wire harness go bad?

asked by: Fred

Helpful Expert Reply:

A wire harness can have wires short out or have a power module go bad. To check, use a circuit tester like # PTW2993. Check the pins when there is no trailer connected. If you only have some functions, check the ground wire for rust or corrosion. If you have a bare metal to metal ground and still have function issues, you can use the circuit tester to trace the wires that don't have function back to their origin. If there is no power there, check a fuse or relay. If power is lost along the way, replace the wire. If power is found before a module but not after it, replace the harness.

I've attached an article on wiring to assist.

expert reply by: Jason S