Troubleshooting Trailer Left Brake Staying On All The Time

Question:

When I hook up a trailer to my truck the left brake light on the trailer will stay on at all time, even if I cut the truck. It does it with any trailer I hook up.

asked by: Aaron R

Expert Reply:

This type of issue typically indicates a short somewhere on the trailer, but since the same problem pops up with different trailers, we know it's actually coming from somewhere on your truck. Most likely there's some damaged wiring on the truck that's shorting out to some nearby metal, or if this is a new harness install - the left brake light wire is tied to the wrong circuit.

What I recommend doing is inspecting any trailer wiring you can access on the truck, looking for exposed or pinched areas that need to be replaced/repaired. Inspect the bumper connector as well for any debris or corrosion that might be built up inside the pins, cleaning out as needed. Lastly, make sure all the connections are secure and correct.

If you continue to have issues please let me know and we'll continue to troubleshoot.

expert reply by: Chris R