Troubleshooting New Wiring Installation Causing Problems with Trailer Lights

Updated 11/12/2018 | Published 11/10/2018

Question:

Over the summer I repainted and rewired my utility trailer. I bought the Hopkins wire kit that has the Y so I didnt need to do extra splicing. I have incandescent lights still on the trailer. When the parking lights or headlights are off on the truck the turn signal and brake lights work. When the headlights or parking lights are on the truck the turn signals and parking lights on the trailer work. However if you press the brake pedal the running lights on the trailer turn off so the trailer has no lights unless you want to turn then only the turn signal flashes but no lights. What could be causing this. Its really weird that everything works as it should except the brake parking lights after it gets dark out. I am thinking of switching to leds but dont want the problem to continue.

asked by: Joey

Expert Reply:

Thank you for the details on the installation of your Hopkins wiring kit like part # HM48244.

Whenever an issue is happening with the lights on a trailer it can typically be traced back to a bad ground. You did install a new wiring harness but since you just painted your trailer the problem is likely some paint that is causing a bad ground.

Check all of the grounds for your lights and be sure that they are secure and connected to a clean, bare-metal surface as even a little paint can cause problems.

expert reply by: Jon G