Troubleshooting Brake Controller Circuit Wiring of Trailer that Shorts Wiring

Question:

If I put a test light on my blue wire for electric brakes I get a flash of light for a split second every time I try that is what I get. I have a trailer with no brakes...just lights and it burnt the wires out on the trailer but, it did not blow any fuses. Ive checked all the grounds that I know of and could not find any bad connections or bad grounds. I have even ripped my fuse box under the hood to look for broken or corroded wires and they look to be in good condition. What would you suggest that I try next so that my trailer brakes will work? All the lights to my trailer with electric brakes work fine. Thanks for your help.

asked by: Daniel D

Expert Reply:

That split second of illumination that your test light is showing on the brake output circuit is normal. That's the controller testing the circuit looking for a trailer connection. When it senses the draw of trailer brake magnets it knows a controller is connected.

Since the trailer's wiring is what burned out/melted the short has to be on the brake output circuit on the trailer. Best option would be to go over the wiring of the circuit from the trailer connector back to the brake assemblies to find where it's shorting to the trailer frame and repair as neede. It could also be a magnet in a brake assembly that's damaged with open wiring touching the drum which would cause a short.

I attached a help article on troubleshooting brake controllers for you to check out as well.

expert reply by: Jameson C