How to Test Trailer Connector Functions on a 1996 GMC Topkick

Updated 02/26/2018 | Published 02/24/2018

Question:

Have a 1996 gsm topkick looking for a diagram showing which terminal is what trailer brakes arent working and Im suspicious it may be wired incorrectly

asked by: John G

Helpful Expert Reply:

I may have a solution for you but unfortunately we do not have any wiring diagrams for a 1996 GMC Topkick.

If you are trying to figure out how the 7-Way at the rear should be wired we do have a picture which shows what the typical layout is (see attached photo on the right side) but it isn't a hard and fast rule that it has to wired that way.

The best way to make sure that the 7-Way is wired how you want it is to simply use a circuit tester # PTW2992 and test the functions of the various pins. You can test the wiring on your trailer connector by grounding the negative terminal on the battery of your Topkick and using the positive terminal to test the pin locations on your trailer.

expert reply by: Jon G