Troubleshooting Trailer Blinkers that Both Blink When Either Turn Signal is Applied

Published 10/22/2014

Question:

I have a 1998 Ford F 150 when I cut my blinker on the left side on my right side blanks just a little I had to put and you pigtail on my truck but when I hook it up by the color of the wires they wont work so I moved my brown wire over to an orange wire and it worked but my blinkers both blink so what am I doing wrong I know Im doing something or I havent check something

asked by: Ricky

Helpful Expert Reply:

It sounds like you have the blinker circuit of your 1998 F150 run to the running lights circuit on your trailer wiring so when the blinker is applied both of your running lights are flashing.

Any time you see trailer lighting that illuminates dimly when the wrong circuit is applied is usually indicates that there is a weak ground on the trailer wiring circuit. How that all works is beyond me, but what you will want to do is return the trailer to the previous wiring configuration you had and then check to make sure that all of the light assemblies are connected to a clean metal surface. A lot of assemblies ground through their mounting hardware so make sure they are attached to a clean metal surface as well. Also make sure the main ground of the wiring harness is run to a clean metal surface on the trailer frame.

Aside from that I would recommend you check the condition of the wiring making sure there are isn't any exposed wire that could cause a short. I attached a couple FAQ articles to the right that should be helpful as well.

expert reply by: Jameson C