Troubleshooting Curt Wiring Harness On 2018 Jeep Compass Causing No Right Turn Signal For Trailer

Question:

I installed the Curt trailer wiring module a few years ago on my daughters 2018 Jeep Compass. It was working properly after install. She hadnt pulled a trailer for awhile, but when getting ready for a trip, we found that the right side lighting on the trailer wasnt working properly. The left side is fine with all functions, but only the running lights work on the right side. Confirmed that trailer was wired properly by plugging into another vehicle, and all trailer lights functioned properly. I also confirmed the connections to the rear light pigtails on both sides. All lights work properly on the Jeep, but the signal is not getting to the trailer plug. So, there is a bad connection going to the 4-flat plug on the jeep that only affects the brake and turn functions on the right side. Is this just likely a failed connection in the Curt module? What is the troubleshooting process from here?

asked by: Trent T

Expert Reply:

Sorry to hear about the issues you're having!

You can test the Curt harness on your daughters 2018 Jeep compass to confirm if the module went bad, or if there is another issue some where.

You'll need a circuit tester like # PTW2993 and test the right side stop/brake function that's not working.

What you'll need to do is turn on the right turn signal and test the wires that T into the right brake light and going into the module. If there's feeding the module, then double check the that 4-way connector is not getting the right turn signal signal.

If you have power feeding the box but not coming out then the module is defective. Nothing's perfect so this kind of thing tends to happen from time to time, but I would check whatever trailer your towing's right turn signal wiring as the most common cause of a module going bad is a short on the trailer wiring.

You mentioned the harness is a few years old so it would not be under warranty as there's only a 1-year warranty, so you'll need either the # C56369 if she has the older body style, or the # C59236 if she has the new body style.