TRUCK BED EXTENSION. Trailer wiring harness is designed to be an extension of your truck's existing towing wiring. It retains the use of the 7-way rear RV blade plug, while adding an additional 7-way plug in the truck bed. EASY TO INSTALL. No cutting! No splicing! This trailer wire extension plugs into your truck's existing factory wiring and features a 7-foot harness for flexible positioning in the truck bed (2-1/8-inch hole saw required for installation) HEAVY DUTY CONNECTOR. The 7-pin trailer wire extension can be used to connect trailer taillights, brake lights, backup lights, turn signals, electric trailer brakes, and an auxiliary power cable. CONSTRUCTION . For use and reliable connection, the 7-pin truck wiring plug housing is made from molded black plastic and features a spring-loaded dust cover to protect the connection points. VEHICLE SPECIFIC. Vehicle trailer wiring extension harness is designed for select , , , , , Ram and , vehicle models, the easiest installation