Troubleshooting T-One Wiring Harness Installation on a 2022 Ford Bronco

Updated 07/07/2022 | Published 07/05/2022

Question:

Recently bought a trailer light wiring kit for my 2022 bronco. The running lights work ok, but turn indicator circuits only are hot measured with a multi meter when the right turn indicator is turned on, and then both indicator/brake leads on the car side plug are hot? Brake light at least the left one on the trailer work.

asked by: Raymond M

Helpful Expert Reply:

Thank you for your purchase of the T-One Vehicle Wiring Harness # TK99VR for your 2022 Ford Bronco!

To start off troubleshooting we'll want to make sure you have the correct harness. The part # TK99VR you have is if your Bronco has LED taillights. If you don't have the LED taillights then you need the T-One # TK33VR instead. It looks like the non-LED setup has the brake function tied in with the turn functions but if you have the LED setup then the brake function has it's own circuit. So you want to double check and make sure your Bronco does in fact have the LED taillights.

The next thing to do is check the functions going into and coming out of the black module box. The incoming signals will be on the different color wiring that tees into your OEM wiring and then you can test the outgoing signals by checking the 4-Way pins with a circuit tester.

If all of that looks good then the issue is on your trailer wiring and you need to find and replace any damaged wiring as well as check all of your ground connections making sure they are secured to a clean, bare-metal surface.

If you aren't getting the correct signals on the 4-Way of the T-One wiring kit then it sounds like the module may be bad and you'll want to get that replaced under the 1-year limited warranty.

Attached are a few videos for you to check out as well as a link to our helpful article on troubleshooting wiring.

expert reply by: Jon G