Lights On Boat Trailer Are Very Dim

Question:

I ran all new wiring and lights to my boat trailer I just bought. I ran yellow and brown down driver side and green and brown down passenger side connected the white ground wire to trailer. I then hooked the trailer to my truck and trailer lights were very dim and when I put the turn signal on both lights blink. Brake lights come on when pressed but still very dim. Truck is all led lighting and trailer lights are not led just normal could this be an issue? Also when I hook the trailer up to my other vehicle which is no equipped with led lights the trailer lights are much brighter but still both lights blink when turn signal is on and when brake is pressed both trailer lights go out. It’s an older trailer that has been painted so I went to each light and sanded the area down to bare metal then did the same for the ground wire on trailer but still having the same issue no changes. Not sure what else to try.

asked by: Andy

Expert Reply:

In regards to the dim lighting, this is almost undoubtedly caused by a poor ground. I know you said that you checked each one but what I recommend doing is running a ground wire from each light up to the main ground for the trailer connector and then re-securing this ground as well with new hardware and a sanded surface. If your boat trailer has an aluminium frame then this must be done. The LED lights on the vehicle would not cause an issue so long as you are using a powered converter but I recommend you check the ground for this harness as well.

In regards to both turn signals blinking, you have power from the left stop/turn signal circuit bleeding into the right stop/turn circuit or vice versa. The most likely place this is happening is inside the trailer connector but it could also be between some of the wires that you just ran.

expert reply by: Conner L