Is A Wiring Adapter Harness Needed to Install Brake Controller on 2008 Chevy Silverado

Question:

i am interested in installing this controller in my 2008 Chevy Silverado 1500 4WD with factory tow package....it has this fuse box under the dash above the brake pedal foto enclosed. If i purchase this brake controller, can you tell me what adapter harness i need and where in the fuse box to plug it in, and what hole should the red wire go into?...Thanks, after you let me know, i will feel a little more confident ordereing it.

asked by: Phil G

Expert Reply:

When GM began manufacturing the New Body Style in 2007, they eliminated the need for a wiring adapter harness (until the 2014 model year, when they went back to using a harness). The tow package wiring harness is bundled up under the dash, and terminates in blunt cut wires. The harness will typically have a white tag attached to it, which would be located directly above the junction box in your photo. (It just missed appearing in your photo.) You'll simply wire the # 90195 P3 brake controller up to this harness, however, the wires won't match up color for color.

The harness will contain a red (or red and black striped), a light blue, a dark blue and a white wire. The red tow package wire supplies 12-volt power to the controller, and would attach to the black wire on the brake controller. The dark blue tow package wire carries the output voltage from the controller to the trailer connector and on to the trailer brakes, and would connect to the blue wire on the controller. The light blue tow package wire connects to the CHMSL (center high mounted stoplight) circuit which tells the controller when the vehicle brakes are being applied. It would connect with the red wire on the controller. The white tow package wire is the ground connection, which would connect to the white ground wire of the brake controller.

If there is an orange wire, it is NOT needed. Simply tape the end of the wire and tuck it up out of the way.

Depending on how your truck was equipped, it might need a connection or two completed under the hood. The help article I have linked you to explains in detail how and where to make these connections.

If you click the provided links, you can see the FAQ article and an installation video showing exactly how this is done.

expert reply by: Mike L