Troubleshooting Brake Controller not Working Except With Manual Override

Question:

2015 gmc with brakerite sd and controller it wont activate brakes by pushing pedal but will with slider in truck. its a disk system .

asked by: Ron

Expert Reply:

I'm not sure which brake controller you purchased from us that you're referring to, though when a controller won't work except when using the manual override the issue is often on the red wire - the stop light wire - which sends a signal to the brake controller. You'll need to use circuit tester # PTW2979 to test the stop light switch wire, which is the wire that only gets power when you step on the brake pedal.

If it does not have power then you likely have a blown fuse that you'll need to find, and to do so check your owner's manual to find the appropriate one.

I have added links to some help articles for you to check out as well on troubleshooting brake controllers that I recommend reading.

expert reply by: Kyle S