Today, on this 2017 Mercedes-Benz Sprinter 3500, we're going to review the T1 Vehicle Wiring Harness with 4-Pole Flat Trailer Connector, part number, 118649.All right, this is what our wiring harness looks like when it's installed on our Sprinter van. You notice all you can see, of course, it's going to be a 4-Pole Wire Harness, with a built-in cover. That it goes on when you're not using it, and… see more >