How to Determine if Trailer Light Converter Box is Fried

Published 04/27/2022

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(196)

$75.02

Hook Probe Circuit Tester

(66)

$14.86

Question:

I have a 2013 Ford Edge sport. I installed the 56 120 harness and everything works perfectly except for the running lights. When I pulled the fuse at the battery and reinstall, the running lights Flash for a millisecond. Also when I go to the rear car light assemblies and disconnect and connect the plug-in connector oh, they flash for a second also. I know its not the trailer because when I attach the trailer to my 95 Jeep Wrangler all the lights run as supposed to. Where do I start to see if I have a bad control unit in the harness?

asked by: Peter R

Expert Reply:

It sounds like it might be the harness but you can check this pretty easily by using a circuit tester like part # PTW2993 to test for voltage on the input side of the box to make sure it's receiving the correct signal as well as on the output side. If nothing is coming out of the box it would be fried.

expert reply by: Jameson C