Troubleshooting No Power on Blue Wire at Connector on 2002 Chevrolet Silverado

Question:

Hello, My truck isnt getting any power back to the blue wire at the plug in the bumper. It came from the factory with trailer setup. I installed a brake controller and it lights up when I step on the brake. All my other wires are good, brake lights, running lights and turn signals. I just do not get any power at the plug in the blue wire for the trailer brakes. Where does that wire start up front in the circuit? Thanks,

asked by: Nick

Helpful Expert Reply:

The blue wire from the brake controller back to the 7-Way connector on your Chevy Silverado is the brake controller output circuit. There are a few possible reasons as to why you aren't getting any power at the connector with the brake pedal depressed or manual override activated on the controller.

First, I recommend simply checking that the brake controller output/gain is turned up. If the power is set too low, then you aren't going to get much voltage on the blue wire or at the connector. Also, when testing the controller, make sure you are using the manual override and not the brake pedal. This is because many proportional brake controllers need the vehicle to actually be moving for the controller to send back voltage when pressing down on the brake pedal.

Next, I recommend testing the brake controller itself to see if it might be the issue. In your Silverado, sever the blue wire a few inches from the back of the brake controller. Then use a circuit tester like # PTW2993 to test the end of the blue wire coming out of the controller. There should only be power on the wire when you apply the manual override. If it shows power at idle, then there is something wrong with the controller and it will need to be replaced.

If the controller tests okay, then reconnect the blue wire and move back to the 7-Way connector at the rear of your truck. Check to see if there is any built-up dirt, debris, or corrosion inside the connector, cleaning as needed.

Test the brake output pin on the connector (5 o'clock) by using the manual override. If there is still no power there, then we at least know the issue is somewhere on the truck side and not on the trailer. Check for any exposed or damaged areas on the blue wire going back from the connector up to the brake controller.

If you still cannot locate the cause for this issue, please let me know and we can continue to troubleshoot.

expert reply by: Chris R