Troubleshooting Trailer Brakes that Lock Up When Headlights Get Turned On

Updated 08/11/2014 | Published 08/09/2014

Question:

When I turn my headlights on my brake controller light goes off and the brakes set up on my trailer. Its on a 2001 chevrolet 1500

asked by: DJ D

Helpful Expert Reply:

Sounds like the running light circuit of your trailer wiring is shorting out to your brake output circuit. This would explain why the brake apply every time your headlights come on. What I would do is first check out the trailer connector on your 2001 Chevy 1500. Check to see if there is any corrosion on the inside or back of the connector. Also check for any bent pins inside the connector or exposed wire leading to the connector.

Next, you will want to repeat this process on the trailer's connector. Somewhere the two circuits are shorting out to each other so if you can't find it there you will need to inspect the wiring of the trailer further.

I attached an FAQ on trailer wiring for you to check out as well.

expert reply by: Jameson C