Gmc Trailer Plug Wiring Diagram Picture. This gmc truck trailer wiring diagram model is more appropriate for. Any idea what this wire is used for assuming its a gm factory thing.
12 pin flat this is an extension of the 7 pin flat. Heres the diagram for 7 pin connector. They also provide a wire for a ground connection.
The second diagram shows two brake lights two indicators two side lights and a fog light.
Red 12 volt auxiliary power. Blue pin for electrical brakes. Brown pin for unwanted markers tail lights and running lights. As the name implies they use four wires to carry out the vital lighting functions.