Troubleshooting Brake Controller that Only Works with Override Lever
Question:
I just bought a 05 yoking Denali and decided to put trailer breaks on it. The controller works when I push the button down and it engages the break lights. When I press on the breaks , the controller does not engage.
asked by: Branden
Expert Reply:
That means your brake controller is not getting a signal on the red wire when the brakes are applied. This is the circuit that when activates tells the controller you are braking and to start slowing down the trailer. First thing I'd check is to make sure the third brake light of your 2005 GMC Yukon is active. Normally a blown third brake light fuse in GM vehicles around yours' age is the culprit for this problem. Next make sure the red wire is connected solidly to the correct circuit that sees 12 volts when the brakes are applied.
