Troubleshooting Trailer Brake Controller Brake Power at 7-Way Without Trailer Connected

Updated 04/13/2018 | Published 04/12/2018

Question:

2007 silverado hd old body , wire harness for trailer ,should there be power to the plug for brakes if trailer is not hooked up? test light shows just a blink does trailer have to be hooked up so truck register hooked fo full power for brakes to work?

asked by: GARRY B

Expert Reply:

When you don't have a trailer hooked up to your 2007 Silverado, the 5 o'clock pin where the brake controller output is, should not have any power until you put a draw on that wire with your test light like circuit tester # PTW2993. As soon as a draw is placed on that pin, there should be a dim light that should increase in intensity as you hit the manual override slide on your controller. A proportional brake controller will not show braking because you are not moving except with the manual override slide.

The small power draw when you connect the tester should cause your controller to register that a trailer is connected. The blinking light may be the signal the controller sends back every so often to see if a trailer is connected.

expert reply by: Jason S