Troubleshooting Trailer Electrical/Brake Controller Problem on Trailer Towed by 1999 Chevy Suburban

Updated 05/20/2016 | Published 05/16/2016

Question:

When I plug my dump trailer in the tail lights of my truck turn on and all the lights on the trailer. I have no electric brakes nor can I use cruise control. All the lights work from what I see and have tested. I have checked the wiring nothing is crossed or touching. The colors are all in the right locations. My truck works fine pulling any trailer but this dump trailer. Could my trailer brake and tail light be switched?

asked by: Cory

Expert Reply:

Have you tried towing the dump trailer with a different vehicle? This would pretty quickly tell you if the problem exists with the tow vehicle or the trailer wiring. If the trailer does the same thing with a different tow vehicle, then you know the problem lies in the trailer wiring.

At first glimpse, I'd be inclined to think that the problem you're having lies in the way the trailer connector on the trailer is wired. Please refer to the trailer wiring FAQ article I've provided to confirm the connector is correctly wired. A damaged or excessively corroded trailer connector could also be part of the problem. Examine the trailer connector terminals where the wires attach. If the terminals are corroded, clean or repair the trailer connector.

The fact that the cruise control isn't working is likely a separate issue. How has the controller been installed? Is it hardwired into the vehicle, or was a brake controller wiring harness used. If the hardwire or wiring harness accesses the wrong wire to gain the brake lamp stoplight switch signal, it can cause the cruise control to malfunction. If the taillight and brake wire were swapped, the trailer brakes would immediately apply as soon as the trailer's running lamps were switched on.

I've linked you to our brake controller installation troubleshooting page as well as our trailer wiring page. I hope you find the articles helpful.

expert reply by: Mike L