7 Way Trailer Wiring Harness | etrailer Quickly and easily install this custom harness to get a 7-way and a 4-way trailer connector on your vehicle. Connector plugs into OEM tow package wiring harness - no cutting or splicing required. Features: Provides both a 7-way RV-style and a 4-pole flat connector at the back of your vehicle to power your trailer's signal lights Designed for use with a factory tow package Compatible Amazon: trailer wiring harness 7 way Trailer Wiring Harness Connector with 7 Way Heavy Duty Trailer Cord - 8 Feet 7 Gang Trailer Junction Box for RV,Trailers,Campers,Caravans,Food Vans Etc, Weatherproof. 4.0 out of 5 stars 8. $31 $ 31. 95. Get it as soon as Mon, Apr 22. FREE Shipping by Amazon.