2018 Ford F-250 Missing Transmission Wiring Harness: 1 The 2018 Ford F-250 has 1 problems reported for missing transmission wiring harness. Average repair cost is $1,400 at 6,000 miles. Used Transmission Wiring Harnesses for the Ford F-250 Used Transmission Wiring Harnesses for the Ford F-250 for Sale. Get a great deal! Our used auto parts locator service will help you get a great deal on the used Ford F-250 transmission wiring harnesses you need for your car, truck, SUV or van.