If your vehicle is not equipped with wiring for towing a trailer, CURT custom wiring is the ideal solution. A custom wiring harness - also called a T-connector - is a simple, plug-and-play electrical device that plugs into your automotive Electric system and provides a standard, universal trailer wiring connection. This is done using 2 or more vehicle-specific, OEM-compatible connectors to plug into the taillight assembly, eliminating the need for cutting, splicing and soldering during installation. Custom wiring harnesses are made vehicle-specific, and while they are not available for all vehicles, they do offer 1 of the fastest, easiest and most secure ways to wire a vehicle for towing. This particular plug-in harness provides a 4-way flat connector socket and is designed to be a custom wiring harness to fit certain years of the Lincoln Nautilus (to verify your vehicle compatibility, see application info).