Troubleshooting Brake Controller in 2014 Chevy Silverado 2500HD that Always Generates Full Power  

Question:

Expert Reply:

Trailer brake controllers use the electrical signal from the brake pedal's brake light switch to tell them to generate power for the trailer brakes. This signal is simply "on or off" and the actual amount of braking power depends on the power and boost levels set on the controller. If the controller is actually sending out a full 12V output signal with the power level set at 0.0 then the unit is damaged.

You can test the controller if you can access the wires at the back of it. If you apply a circuit tester like # PTW2992 to the BLUE output wire you can determine if brake power is leaving the controller when it should not. If you have power on the blue wire without pressing the brake pedal or the manual override lever then either the controller is damaged or its RED wire is connected to the wrong vehicle wire. The red wire needs to connect to the COLD side of the brake light switch, which carries power ONLY when you press the brake pedal.

But there is another possibility which is that a corrosion issue in the trailer connector or a short in your wiring is causing the 12V auxiliary power circuit to bleed over into the brake circuit; this would cause the trailer brakes to lock up even with the controller set to zero power. You can inspect your 7-way socket, the connector that plugs into the back of it and the wiring upstream of that connector looking for corrosion, worn insulation or even trapped foreign material or water that could be bridging the 12V power circuit to the brake circuit.

expert reply by: Adam R

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