7 Pin Trailer Wiring Harness | etrailer Install a 7-way, RV-style trailer connector on your vehicle with this easy-to-splice harnessLite draws power directly from the battery to avoid overloading your vehicle's circuits. Brake electrical system Includes harness with 4-pin connection point for plugging in a brake controller wiring adapter (sold separately) Supplies required fuses, wire taps, and additional hardware Constructed Amazon: trailer wiring harness 7 way 7 Way Trailer Cord, Kohree Heavy Duty 7 Way Trailer Plug Inline Cord Wire Harness Cable Double Prongs Connector 8 Feet for Truck Camper Blade Molded RV Cable Wire, Weatherproof Anti-corrosive. 4.4 out of 5 stars 44. $22 $ 22. 99. Get it as soon as Wed, Jul 31.