Troubleshooting Brake Lights On Trailer Not Working But All Other Lights Work

Question:

I have all lights working on my trailer with a diff. Truck, when I plug the truck that is intended to pull this trailer my brake lights won’t work but everything else does I have tested this with 3 different trucks with the same result. I have determined the truck has the problem since the other trucks when plugged into the same trailer everything works. I also tested this truck on different trailers and have the same issues.

asked by: Joe

Expert Reply:

Since you have already found that the issue is with your truck and not the trailer you will need to check the fuses as more than likely the fuse for this function of the towing package is blown.

The only other two options are all on the trailer, being a bad ground or the brake lights pulling too much power, but since the trailer works perfect with other trucks the issue will be a fuse.

I included a link to a helpful article on trailer wiring for you to take a look at.

expert reply by: Samuel C