Troubleshooting Brake Controller with No Brake Power on 2014 Chevy Silverado 1500

Question:

Has worked fine for almost 3 years with a Primus IQ controller, than 2 days ago a problem started. Pulling a 2 horse trailer which is working great when pulled by another vehicle, but not my Silverado now. The trailer brakes, magnets etc. have all been checked, so its not a trailer problem. My brake controller turn to max. will not stop the trailer using the brake. I get a little help by using the controller manual slide knob. Thinking its a bad controller, I installed a prodigy controller, same result, no brakes. We tested the blue wire at the 7 way connector and are getting very low voltage when applying the brakes and slightly more voltage using the slide knob, but nothing near 12 volts. No corrosion present at the 7 way connector and ground is good. Why a problem now and not in the first 2-3 years? And what is my problem?

asked by: David B

Expert Reply:

You've done a great job troubleshooting so far. Since you've ruled out the trailer and have replaced the brake controller, the issue has to be somewhere in the truck itself. You will need to sever the blue wire going into the brake controller approximately 6" back from the brake controller to test the output there. If there is a short somewhere on the blue wire, probing the wire without cutting it will not give an accurate reading. The best solution may be to replace the blue electric brake wire with # 10-1-1 from the back of brake controller all the way to the 7 way. You'll also need some butt connectors, # DW05745-5.

I've attached an article on testing brake controls and troubleshooting brake controller installations. I've also attached a diagram showing the 7-way connector wiring.

expert reply by: Amy W