Plug and Play Trailer Wiring, 2014-18 FLH/FLT models with 4-Wire Trailer Safely and effectively apply the load from your trailer lighting to the battery and not to the rest of the bike's electrical system Eliminate overloading stock lighting or accessory circuits Our relay harness utilizes inputs from the motorcycle to direct power from the battery to the appropriate trailer lighting circuit 4 Wire Plus 1: Our kits provide standard 4-wire output (run, left turn/brake, right turn/brake, ground) plus a bonus wire that can be connected as needed to provide fused 12v power to the trailer for compartment lights or keyless entry systems that are wired independently of the trailers essential lighting 4-Wire Kits include flat-4 connector