Troubleshooting Led Light Turn Signal Flashing Both Sides Only When Headlights Are On

Question:

I have a 2007 Honda Pilot. Turn signal and brake light work when head lights are off. When turned on together both right and left led lights flash, no matter which signal I turn on. I have tried putting a led resistor in line with both the high and low line. Don’t understand why it’s not working. I’m a sending pictures.

asked by: Harry H

Expert Reply:

With your trailer lights, the headlights changing the function of the other lights most likely means you have a ground issue on your trailer. You will want to make sure not only the trailer light # STL8RB has a bare metal to metal ground at the ring terminal on the white wire without any corrosion or debris (even paint can be an issue), but you will also want to make sure your main trailer ground is bare metal to metal with no corrosion as well.

Next check the ground on your trailer wiring harness on your vehicle. This connection also needs to be bare metal to metal and free of any corrosion. I've attached a couple articles to assist.

Your running lights will have more power when your head lights are turned on, so there is a bleed over from a poor ground somewhere in your system. You will also want to make sure the load resistors you installed were installed correctly as they should have each added a ground connection as well.

expert reply by: Jason S