problem with electric trailer brake

[redrum]

Doerider,

I am intimately aware of the issue here. Unfortunately most GM technicians are not so asking them will just confuse the issue.

Your trailer brake controller requires 4 wires to work properly
1) + Positive lead
2) – Negative ground
3) Brake light switch
4) Brake controller lead to rear hitch


GM neglected to terminate the brake light switch and brake controller lead in the convenience center. You have a couple options.

Option One:
Locate the brake light switch and brake controller lead (blue and red) wires that are located underneath the fuse box in the engine compartment. You will have to remove the fuse box to get to them. There are four bolts holding the fuse box down.

The easiest way to get them hooked up is to bring them through the firewall to the convenience center or directly to your tekonsha wires.

If you have the grille mounted spotlights, GM plugged their terminating connector into the trailer brake controller location (Top – second from the left) in the convenience center.

You can share that connection for the trailer brake controller and spotlights, by splicing the wires into the spotlight wires but I do not recommend it. Since the only reason you need to use that cavity is because you need (+) and (-), I suggest you pull a (+) and (-) from the engine compartment while you are pulling the brake light switch and brake controller lead. . This way you can use the spotlights and brake controller without sharing the same plug. You can also Find a (+) and (-) on one of the other spare cavities on the convenience center. Just use a 12 volt tester. They are there.


Option Two:
If you don’t want to pull wires from the firewall you can

A) BRAKE LIGHT SWITCH: Connect a wire from your tekonsha to the fuse box located on the left side of the dash near the drivers side door. You will find the “brake light switch” fuse in that fuse box.
B) BRAKE CONTROLLER LEAD: Pull a wire from your tekonsha directly back to the trailer hitch plug and terminate it at the plug.
C) Find a (+) and (-) on one of the other spare cavities on the convenience center.


Option Three:
Take it to an authorized dealer and have them hook it up. You will have to educate the GM personnel about this situation. There are three bulletins out on GM trailer brake connections but they do not apply to the H2. GM changed its wiring harness in 1999 and most GM techs will try to tell you to
A) Just plug in the stock GM 3015 connector.
B) Switch a couple of wires at the terminator or
C) Jump a couple of wires at the terminator.

DOING A,B, OR C WILL GET YOU NOWHERE FAST. THIS DOES NOT APPLY TO THE H2. GM has not yet sent out a TSB specifically for the H2. The GM bulletins apply to other GM trucks.

I can send you complete schematics and pictures if you like.