Stop Light Switch Wire on 1992 GMC Sierra for Brake Controller

Question:

1992 GMC Sierra XLT Brake Light Wire. Need some help figuring out which wire to tap into on my GMC to install a brake controller. Looks like I have 4 to choose from and Im not having any luck with the circuit tester provided with the install kit, keep stabbing myself in the finger with it.

asked by: Jim D

Expert Reply:

While the circuit tester is truly the only way to find the correct wire for you to install the Curt TriFlex Trailer Brake Controller # C24VV with Wiring Adapter # C51515 on your 1992 GMC Sierra, what I can tell you is that when we installed this same controller in a '94 Chevy C/K, which will be similar to your truck, the wire was yellow, as you can see by the linked installation video.

That said, wire colors are not universal and vary from year to year and manufacturer so yours very well could be different. You are simply looking for the wire that shows power when you apply the brake pedal.

expert reply by: Kyle S