Troubleshooting Trailer Brake Lights Not Functioning after Wiring Harness Install 2011 Nissan Cube

Question:

We installed the wiring, and everything works except the brake lights. Could it be a faulty wiring harness? Or is there something we could have done wrong?

asked by: Stacy P

Expert Reply:

The first thing you will want to do is test the 4-way of the # 118492 that you installed with a circuit tester like part # PTW2993. See the video I attached to see how this is done. This will tell you if the problem is on the vehicle side or trailer side of the wiring.

I suspect the problem is on the trailer and it is that the grounds of the light assemblies aren't strong enough. Check to make sure the assemblies are grounded to a clean metal surface. Do the same for the main ground wire that runs from the trailer connector to the trailer frame.

If the problem is on the vehicle side it could be that the harness is bad. To determine this check out the video I attached that details how to test the box.

I also attached an FAQ on troubleshooting 4-way installs for you to check out.

expert reply by: Jameson C