Turn Signals Work But Brake Lights Do Not Light Up

Published 04/17/2015

Question:

the blinkers work, but no brake lights when then the brake pedal is pushed

asked by: Jim

Expert Reply:

You came from a brake controller page when you asked the question. Is this issue related to the installation of the brake controller? Or are we just talking about brake lights on a trailer or vehicle?

If it is on the trailer then usually there is a bad ground connection since the brake lights draw more constant power than the turn signals. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.

The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

If the issue is on the vehicle then use the owners manual to find the fuse location(s) for the stop light or CHMSL fuse(s). CHMSL stands for center high mount stop lamp. I have also included a link to troubleshooting vehicle side trailer wiring harnesses.

expert reply by: Michael H