Trailer Brake Lamps Stay On When Running Lamps Are Switched On

Question:

The trailer brake lights function properly when the tail lights are off. When the tail lights are on, the brake lights stay on even after the brake pedal is released.

asked by: Steve

Expert Reply:

When you have trailer taillights that function properly until the running lights are switched on, it's caused by a poor/insufficient ground connection.

You'll want to check the main ground on the trailer, where the ground wire from the trailer connector attaches to the trailer frame, usually on the trailer tongue. Make sure this connection is securely made to clean, bare metal. Each lamp should be grounded as well, either by a ground wire or through the hardware used to fasten it to the trailer.

Once you have good ground connections, the problem you describe should go away. I'll link you to some trailer wiring and troubleshooting articles that you might find helpful. A circuit tester like # PTW2993 can come in handy during troubleshooting.

expert reply by: Mike L