Wiring Harness For Rv | etrailer Extend your factory harness to a new location or add a different style connector without having to remove your factory harness with this handy 3' extension. Features: Wiring harness extends your vehicle's 7-way RV-style trailer connector One end of wiring harness plugs into the back of your existing 7-way Other end hardwires into new connector (sold Amazon: camper wiring harness Proline Power 7-Way Plug Inline Trailer Wiring Harness Cord, Camper, Truck, Weatherproof and Corrosion Resistant 14 Feet In Length, Loose End. 3.5 out of 5 stars 8. $34 $ 34. 99. Get it as soon as Mon, Jun 10. FREE Shipping by Amazon.