Flat Towing 2015 GMC Sierra 1500 Pickup

Question:

Do I need to purchase any other wiring kit to install a road master sterling tow bar and Air Force one braking system.

asked by: Tim

Expert Reply:

To flat tow a 2015 GMC Sierra 1500 you will need the following parts.

First you will need a towed vehicle specific Base Plate Kit. I recommend the Roadmaster # RM-3177-3 kit. This Direct-Connect kit is designed for full size trucks eliminating the need for crossbars.

Next you need a tow bar. The Roadmaster # RM-576 “Sterling” All Terrain and Non-Binding tow bar that you mentioned will work great and include the safety cables. A non-binding tow bar will let you easily disconnect your tow bar even if your coach and towed vehicle is not on level ground or at a difficult angle. The two bar is the one point in flat towing that gets the most stress and wear.

Next you will need a tow bar wiring kit. I recommend the Roadmaster RM-152-98146-7 Universal wiring kit which includes everything you need to connect your RV's tail, brake, and turn signal lights to your towed car. Diodes prevent feedback and wire your car to operate as a combined system. Includes a 7-way to 6-way straight adapter cord. When you do finally get ready to plug your electrical cables in I would put a little Edelmann # 11755 dielectric grease on those connections. The dielectric grease will keep help keep moisture and corrosion out of your connections.

Your Sierra will additionally need a Roadmaster # RM-766 battery disconnect switch. Alternatively you can manually disconnect the battery in the towed vehicle when flat towed.

Your Sierra weighs in around 5000 pounds so you will need a supplemental braking system installed in it. This will improve braking and handling, and extend the life of your coaches braking system. Additionally, most states require supplemental braking if your towed vehicle is over 3000 pounds. If your coach has traditional hydraulic brakes then I recommend the Brake Buddy # HM39524 portable system that has proportional braking and has a wireless display for your cab so you can see your braking system status or change profiles from your driver's seat.

If your coach has air brakes, then instead of the Brake Buddy system, you will need the Demco # DM26VR “Air Force One” supplemental braking system for air brakes. This is the system that you mentioned.