Safely & properly apply the load from the trailer lighting to the battery & not to the rest of the bike s wiring/relays/fuses with this Trailer Wiring Harness & Relay. Select the Universal or GoldWing specific Plug-&-Play kit that plugs inline to the bike s main rear harness. All kits finish up by connecting directly to your battery & wiring to your trailer plug. Add the 5 to 4 Converter for trailers with 4-wire connectors & it plugs right inline to the Kuryakyn Trailer Wiring Harness & Relay. This is the easiest wiring you ll ever have to do.