Troubleshooting Brake Controller When Trailer Brakes Dont Apply Unless Manual Override Is Used

Updated 03/27/2017 | Published 03/24/2017

Products Featured in This Question

Draw-Tite Activator IV Trailer Brake Controller - Up to 4 Axles - Time Delayed

(357)

$103.31

Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers - GM

(1194)

$19.55

Hook Probe Circuit Tester

(60)

$12.27

Question:

Have following 2006 Chevy 3500 diesel Aftermarket flat bed Gooseneck trailer Label gone but believe Reese brake controller 3015 adapter Both red wire under fuse panel connected to positive posts Have green led light on controller When I press brake pedal led stays green brake lights come on and truck applies brakes, trailer brakes dont apply When I hit Manuel tab for trailer brakes light on controller turns red and applies trailer brakes Any ideas ? I didnt install brake controller but think installer missed something

asked by: Gene

Helpful Expert Reply:

It sounds like there is an installation issue or a short in how your brake controller is connected. Since you have the manual override, it is likely that your brake controller is not malfunctioning. It sounds like the red wire from your brake controller that should be connected to your tail light switch either isn't connected or has a short. I recommend using a circuit tester like # PTW2993 to test that tail light wire for function. It should be giving a signal on the cold side when the brake pedal is pressed but not when it is not. You should be able to see this clearly with that incandescent circuit tester. If there is a short, you will need to replace the adapter # 3015-P. If the problem is further involved than that, you will want to take your vehicle to your local dealer.

I've attached some articles to assist.

expert reply by: Jason S