How to Easily Determine if Converter of Trailer Wiring Harness is Bad

Updated 08/24/2021 | Published 08/23/2021

Products Featured in This Question

Hook Probe Circuit Tester

(70)

$13.94

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

(41)

$39.90

Question:

I have purchased through eBay and installed a trailer light wiring harness on my vehicle, but only the turn signals work. I don’t know what’s wrong with it. I believe it was claimed to be new and unused, but enough time has passed that I can no longer contact the seller for assistance. My question is whether you believe that this Mopar adapter could be diagnosed and possibly have wiring changed on plug-in connectors that may not be exactly right for my vehicle, or whether it would be quicker, easier and more economical just to start over with a new harness from a reputable online retailer like etrailer.com for try again.

asked by: James W

Expert Reply:

To troubleshoot whether or not a trailer wiring harness converter box is functional you just need a circuit tester like part # PTW2993 to test for voltage on all of the circuits on the input side of the box and then if they are all there then test the output side. If the box is bad you'll find voltage on the input side but none on the output side. At this point it would be best to replace the entire setup with something like the Curt # C55376.

expert reply by: Jameson C