Trailer Lights Blink When Head Lights Are Turned On But Function Normally Otherwise

Question:

Hello, All my trailer lights blink when I turn on my left or right blinker, but this only happens when my head lights are on. If the headlights are off they all work correctly. I have checked all my ground on the trailer and truck. The same thing happens when i use my temporary towing light system. thanks

asked by: David S

Expert Reply:

Since this is only occurring when you turn on the headlights, it sounds like there is some sort of overload in the system either caused by a short (due to an exposed wire) or too many lights- when you turn your headlights on, those lights are now drawing on the system and it could be them joining the system that is causing the overload.

First I would recommend going through your trailer's light wires to make sure that none of the wires are cut/damaged where an exposed wire is touching the metal frame; any wire that is contacting the metal trailer frame could be the source of a short that is causing your issues.

If there aren't any exposed wires, check the wiring harness on your vehicle to see if there is a maximum amperage rating; from there you'll need to determine amperage draw of trailer lights and confirm that lights do not draw more power than the harness can handle. I've attached a link to one of our troubleshooting articles that shows some of the common trailer lights and their amp draw but you'll want to check to make sure that you don't have too many lights drawing power.

If you've gone through these initial steps and you haven't located the source of your problem, let me know and I can give you a couple of other things to look at and continue to help you troubleshoot this issue.

expert reply by: Erik B