Troubleshooting Trailer Right Signal and Left Brake Stops Working with Headlights On

Question:

When the running lights are on, only the right light comes on. The right light will not blink when right turn signal is on. The left light will blink when left turn signal is on. Both work the same with or without running lights. Brake lights, only the right light comes on.

asked by: Kevin T

Expert Reply:

When the headlights being switched on cause trailer light problems this either means that you have too many lights on the trailer or you have a bad ground somewhere. If your trailer just started doing this and you haven't swapped out or added any lights then a bad ground is the place to start.

Check the grounds both on your trailer and your tow vehicle and make sure that they are securely connected to a clean, bare-metal surface. Sometimes even some paint can cause issues so if you just recently updated the paint on your trailer that can be the culprit.

I have attached a helpful article on troubleshooting trailer lights that you can reference but if you try the steps mentioned above and nothing changes let me know and I can help you troubleshoot further.

expert reply by: Jon G