Troubleshooting Trailer Lights Not Functioning When Headlights are On

Question:

My brake lights, signal lights left and right ,flashers all work. When I turn on the main lights to the truck , truck light work but trailer light do not work. Do you think this is a fuse or a wiring problem? I have a Ford 2001 F-150 4x4, 5.4 engine, 8 cylinder.

asked by: Steve L

Expert Reply:

It sounds like there is too much amperage being drawn on your trailer when the headlights are on and it is too much for the trailer so everything shuts off. This could be because of a bad ground somewhere.

First thing I would do is check the grounds on the trailer for any loose wiring and corrosion and fix as necessary. If the grounds are good you might need to convert your trailer lights to LED lights so as to minimize the draw on the trailer light circuits.

expert reply by: Jameson C