Correct Wiring Harness for the Curt Triflex Brake Controller


I was looking at a Curt Triflex brake controller, but I am having trouble verifying the correct wiring harness to install it into a 2008 GMC Denali XL. My initial finding is the C51342, but I am not sure. Can you help?


Expert Reply:

The Curt Triflex brake controller # C51140 is an excellent choice when adding a brake controller to your vehicle. This brake controller activates trailer brakes in proportion to your vehicle's braking action, automatically adjusts trailer's braking based on deceleration of tow vehicle, and activates immediately with no pausing like with time-delayed brake controllers.

But when trying to find the correct wiring harness to install it into a 2008 GMC Denali XL, the answer is the Universal Wiring Adapter for Curt Trailer Brake Controllers Item # C51515. This wiring adapter is designed for vehicles that do not come equipped with a factory brake control wiring harness port. This 2008 GMC Denali XL is one of the vehicles that have all the wires run but there is no connecter to plug the adapter in. One end plugs into your Curt trailer brake controller while the other end splices into your vehicle's wiring. The Deka Heat Shrink Butt Connectors # DW05745-5 will be what u need to get the job done.

The wiring harness in the vehicle is located under the dash between the ebrake and brake pedal. Look for a bundle of wires with a white tag hanging off it. Wires connect as follows:

Red vehicle wire to black brake controller harness wire
White vehicle wire to white brake controller harness wire
Light blue/white striped wire on vehicle to red brake control harness wire
Dark blue vehicle wire to blue brake control harness wire
Orange wire on vehicle isn't often used.

In order to make your brake controller # C51140 and the Wiring Adapter # C51515 work, you will
need a Custom Multi-Tow 7-Way and 4-Way Trailer Connectors # 30955. This will allow you to have a 7-way connection at the back of your vehicle to connect to your trailer.

Attached are videos of the brake controller and wiring harness installations.

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