How To Find the Right Brake Switch Wire to Install a Brake Controller on a 1999 GMC Yukon

Question:

This video is very good. The time and effort spent on showing where the tow-package-installed blue and redorange wires are is valuable. Thanks! I appreciate the time spent in the video showing us how to repeatedly use crimp-on connectors,however, I think the time would have been better spent showing where and how the cold-side wire for the brake controller can be found. There are more complaints on line about how difficult this is, but none that I have seen asking for more examples of using crimp connectors. Since the whole operation hinges on finding the right cold-side wire, and since it is a pain in the keister to do, a little more time in explanation would have been helpful. So, how does one find that wire?

asked by: Shannon M

Expert Reply:

If we ever have a 1999 GMC Yukon in to install a brake controller, rest assured that we will most definitely point out which is the brake switch wire to connect to.

But in the meantime, I can tell you exactly how to find it. Like it says in the supporting documents for installation kit # ETBC7, you will need to use a circuit tester such as # PTW2993 to aid in finding the correct wire.

You will probe the brake switch wires, located above the brake pedal, until you find the one that has power only when the brake pedal is pressed. If it has power at any other time, such as with the headlights or turn signals on, it is not the correct wire.

I do know that on a 1999 Suburban it is a white brake switch wire. But that could be completely different than a Yukon, so testing is required.

expert reply by: Michael H