Easily route towing electrical functi Easily route towing electrical functions into the truck bed for 5th wheel and gooseneck trailers, while retaining electrical functions at the rear bumper of the vehicle. This harness allows you to directly plug into the factory USCAR connector under the truck and has terminated wires at the other end so you can hardwire different styles of plugs for use inside the truck bed. This harness allows you to directly plug into the factory USCAR connector under the truck and has terminated wires at the other end so you can hardwire different styles of plugs for use inside the truck bed