Found a Loose White Wire on My Trailer, Where Does It Go

Updated 02/04/2020 | Published 02/03/2020

Question:

I have trailer lights on my trailer and I have a white wire that is not go to the plug it’s just kind of hanging what do I attach it to I noticed you said it is the ground wire but where do you attach it on the trailer or on the truck

asked by: Marty

Expert Reply:

It sounds like there is a white wire coming from the 4 or 7 way connector on your trailer that is not currently connected to anything; in most cases that is the ground wire, and it should be connected to a paint and corrosion free spot on the frame of the trailer. You'll want to use a ring terminal connector like the # DW05702-1 connected to the ground wire and then connect the terminal to the frame with a screw.

You'll want to verify the functions of each wire on your trailer, but if you've got a 4 way connector it'll be fairly easy to trace the wiring to determine each function (so you can be sure the white wire is the ground wire). On a 4 way, the wires are normally wired in this manner:

Green: Right Turn Signal
Yellow: Left Turn Signal
Brown: Tail Lights/Side Marker
White: Ground

I would also recommend checking the 4 way connector itself to make sure that the white wire running off of it isn't already connected to the trailer. If this is an older trailer that you maybe just purchased, it could be that someone has replaced the ground and accidentally left a loose wire.

I've linked some helpful wiring articles that will explain how to install and troubleshoot both a 4 way and 7 way connector.