Troubleshooting Trailer Wiring Where Blinkers Only Work with Headlights Off

Published 08/30/2019

Question:

I purchased a different brand LED trailer light set. These new lights work fine when the headlights are off. However when the headlights/taillights are on there is no change in brightness. Or no turn or brake lights. I have checked voltage. I get 12+ for the taillights but only about 4-5 to to wire for the turn/stop function. I have tried with two different tow vehicle and both do the same thing. The second vehicle regularly tows a smaller boat with LED lights. What are my chances that your lights will work?

asked by: Conrad

Expert Reply:

Sounds like your issue is that you have the running light circuit wiring ran to the brighter stop/turn illumination circuit of the lighting. So what you'd want to do is reverse the wiring of the two circuits. Either at the connector or at the lights (whichever is easiest) and you'd have the issue handled!

expert reply by: Jameson C