Parts Needed to Flat Tow 2015-2018 GMC Sierra 2500 4WD Behind RV

Question:

Looking at getting a new Sierra 2500 - thinking 2015-2018 4WD model. Want to be able to tow it behind our RV, can you recommend what parts I would need?

asked by: Trevor

Expert Reply:

In order to flat tow your GMC Sierra 2500 with 4WD behind an RV, you will need a base plate kit, a tow bar, safety cables, a lighting solution, a supplemental braking system, and most likely a high-low adapter.

Starting with the base plates, I recommend the Roadmaster MS Base Plate Kit # RM-3180-2. These heavy-duty brackets are confirmed to fit the 2015-2018 Sierra and their all-steel construction provides exceptional strength for pulling the vehicle. All the needed mounting hardware is included.

For a compatible tow bar that will work great with your Sierra I highly recommend the Roadmaster Nighthawk All Terrain # RM-676. This is an excellent, non-binding tow bar that features a self-aligning design, extra-long telescoping arms for better maneuverability, and integrated LED lights that illuminate with your RV tail lights for greater visibility. It has an 8,000 pound towing weight capacity and safety cables are included so you won't need to purchase those separately.

I do recommend adding the Tow Bar Cover # RM-055-3. This will help keep the unit free of dirt and road grime to ensure smooth operation as your trips start to add up.

Then for a lighting solution I really like the Roadmaster Hy-Power Diode Wiring Kit # RM-152. This kit lets you use the Sierra's tail lights and wiring system while also preventing any feedback from the RV. You can use the 6-Way to 7-Way connector harness that is included with the above-mentioned Nighthawk Tow Bar to connect with the RV. Also keep in mind that the Sierra's battery will need to be disconnected for towing (you can check your copy of the owner's manual to verify). To simplify this process I recommend adding the Automatic Battery Disconnect # RM-766. This will let you disconnect the battery with with flip of a switch.

For a supplemental braking system, I recommend the SMI Stay-IN-Play DUO # SM99251. This is great proportional system that activates the Sierra's brakes at the same time and with the same intensity that you apply to them in your RV. The best thing about this system is that after the initial installation it requires very little attention as you transition from flat towing to everyday driving (and vice versa). The Stop Light Switch # RM-751463 is also needed to ensure proper operation of the system.

If you plan on towing the vehicle for long periods at a time, I also recommend the Charge Line Kit # RM-156-25. This kit allows up to 15 amps from the RV's battery to be used to maintain the charge on the Sierra's battery while you're traveling.

Finally, you will likely need a high-low adapter like the Roadmaster # RM-076 to keep your tow bar within the "Safety Zone" (3 inches above or below level). This particular adapter features a rise or drop of 6 inches. I have attached a great article that explains how to determine the correct adapter for your setup if the rise or drop on this unit is not sufficient.

I have also included video demonstrations and written installation instructions for the products mentioned, along with an article on flat towing that you might find helpful.