Trailer Wiring Colors 4 Pin. The wire colors are Black/White (ground), Blue/White (Battery voltage via "Smart Junction Box" in right kick panel), and Green (input circuit to Instrument They give color codes and detailed info. Wiring your four-pin trailer can be a challenge when you first do it, but it's a simple do-it-yourself task.
Trailer-Vehicle Connector Wiring. by James W. It was an aftermarket add on I did when the original trailer connector on the truck broke off. The circuits are for left and right brake lights and running lights.
Then install the replacement flat four pin connector, making sure to connect the correct trailer wire colors to each.
Learn all about trailer wiring at HowStuffWorks.
The first step in wiring your trailer cables is to ground the white cable first. This type of connector is normally found on UTVs, ATVs and trailers that do not have their own braking system. Trailer Wiring Diagrams showing you the typical wiring for most single axle trailer and tandem axle trailers.