Electric Brake Wire Location on a 2005 GMC Savana Van

Question:

I found the stock brake control wire harness under my dash. But cant find the same brake control wire in the rear of my van. There are 3 stock wiring harness on the drivers side rear. That are not pluged into anything. One had purple,black,tan, and a white wire. One harness 2 wires one red\white and a black wire. 2 of the wires that go to my brake controler. And the last one has 2 orange a grey a white a brown and a blue wire

asked by: Conor

Expert Reply:

The electric brake wire on the 2005 GMC Savana Van models would be connected in one of two ways. If your van came equipped with a factory 7-Way, then the blue brake wire is already ran from the 7-Way plug in the back of the vehicle and up into the cab. You would not make a connection in the rear of the vehicle. The wire would be located under the dash, near the emergency brake pedal.

You will need to hard wire to install a brake controller, as the 2005 Savana vans should not have any factory brake control port. The brake controller wire connections would be made as follows.

White: Ground, attached to a clean piece of unpainted metal.
Black: 12v lead, attached to the vehicle positive battery terminal with a 20amp or 30amp circuit breaker, parts # 9506P or # 38630 respectively. You would use the 20amp breaker for a trailer with 2 to 4 brakes, or the 30-amp for trailers with 6 to 8 brakes.
Blue: Electric brakes, attached to the blue electric brake wire from the 7-way plug.
Red: Stoplight switch, normally located directly off the vehicle brake pedal. Use a light tester like our part # PTW2993 to determine which wire receives power when the brake pedal is pressed and goes cold when the pedal is released.

If your van does not have the factory 7-Way plug, then you would need to run the electric brake wire from back to front. I would recommend using brake control installation kit # ETBC7, as this would include a 4 to 7-Way adapter, as well as the rest of the items needed to hook up the brake controller. You would not need additional circuit breakers as mentioned above, but the connections would be made as I described. Please note that you would first need a 4-Way plug onto which the adapter could be installed, like our custom-fit wiring # 31345.

To install the 4 to 7-Way adapter from the installation kit, you would plug it into the 4-Way connector and then hook up the additional wires as follows.

Blue: Electric brakes, attached to the blue electric brake wire from the brake controller.
White: Ground, attached to a clean piece of unpainted metal on the vehicle frame.
Black: 12v lead, attached to the vehicle positive battery terminal with a 40amp circuit breaker, included in the kit.
Purple: Auxiliary wire, usually used to power reverse lights on the trailer, if present. This wire can be tied up if not needed.

I am including some additional information on wiring for a brake controller that should be helpful for you, as well as a video featuring a typical installation on a similar van.