Troubleshooting Trailer Taillights that all Blink with Blinker When Headlights are On

Question:

7 pin ..i have good running lights,good brake lights,,good lt and rt turn signal...but here is my trouble with running light on when i use lt or rt turn signal all four marker lights blink also ,they only do this when running lights are on,, its very very faint but they are blinking.... good ground clean ground,,,,help any ideas

asked by: Tom G

Expert Reply:

I know you said the ground is good, but when we see this type of circuit bleed-over it's because of an insufficient ground. The larger draw is basically too much for your current ground and is basically trying to ground back through the other lights on the trailer which is causing the problem you see.

Try running all of the ground wires back to the main ground wire of the trailer and see if that fixes the problem.

expert reply by: Jameson C