How To Wire Boat Trailer Lights March 26, 2019 Boat Trailer Wiring Tips From BoatUS . Trailer wiring is simple enough, but trailer lights can be a source of frustration for boaters. Here are some tips from BoatUS to make them more dependable. www.bdoutdoors.com 3 Way Key SwitchHeater Wiring DiagramWiring Fan To Light Switch2 Prong SwitchThree Way Plug WiringPwm Box Mod Wiring DiagramParts Of A Trailer Hitch Diagram14 Gauge Electrical Wire