2015 Ford F-150 Trailer Wiring | etrailer Call 800-298-8924 to get Expert Service ordering a Trailer Wiring for your 2015 Ford F-150. Complete installation instructions and lifetime technical support on all Trailer Wiring purchases. Lowest price guarantee on accessories for your Ford F-150 and the fastest shipping available. Trailer Hitch Wiring Harness - 4 Pin - Ford Accessories This 4-pin wiring harness assembly is made to plug into the factory electrical system. The 4-pin design does not allow the use of trailers with electric brakes. Dealer installation recommended. .