Troubleshooting 2015 Jeep Grand Cherokee 4 Flat Trailer Wiring Install

Question:

Wiring trailer lights to my 2015 jeep grand Cherokee with a 4 pin flat adapter from my rear lights, not the 7 pin installed connection that Jeep activated. Is there a Relay in the fuse box also associated with this wiring? I replaced fuses 81,53,28,29 and 30 and still no lights work on the trailer. Trailer is newly bought and assembled and everything looks wired and grounded correctly on jeep and trailer. Directions did not state to remove the new paint on trailer to get ground. Can the Curt black converter box be bad? How do I check that other than getting 1-2 volts on volt meter in the 4 pin? This is maddening so any help with be much appreciated!

asked by: Dave

Expert Reply:

We do not show any relays on the 2015 Jeep Grand Cherokee. There are a few things you can look at to help narrow down the source of the issue.

Since you have already replaced the fuses, it will definitely be worthwhile to test the converter. The best way to do this is with a wire tester like part # PTW2993. You will want to first test each input signal on the converter module. If the incoming wires test normally, but not on the output wires, then you are dealing with a bad module. It is actually not unheard of for the modules to go bad. If you are not getting proper signal on the input side of the module, then we can narrow it down to something on the vehicle side.

I will add that generally we do recommend using a good clean ground location, free of any paint or corrosion. So that will be worth checking as well.

expert reply by: Jesse M