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: 7 wire trailer harness BougeRV 7 Way Trailer Plug Weatherproof Trailer Wiring Harness 7 Pin Trailer Connector with Junction Box for RV Trailers, Campers, Caravans, Food Trucks (8 Feet Long) 4.6 out of 5 stars 67. $27 $ 27. 89. Get it as soon as Fri, Apr 19. FREE Shipping by Amazon.