Recommended Flat Tow Wiring for a 2025 GMC Sierra 1500
Updated 09/29/2025 | Published 05/07/2025
Products Featured in This Question
Question:
i need to tow my 2025 gmc behind my motor coach do you have a wiring harness for it
asked by: Howard W
Expert Reply:
We sure do Howard! To control your 2025 GMC Sierra 1500's lights you'll need the Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles item # RM-15267. This kit includes all the wiring, diodes, umbilical cable, and connectors needed to set your truck up to be flat towed behind a motorhome.
Here are the rest of the parts you'll need to flat tow your 2025 GMC Sierra 1500, including some additional wiring requirements:
Tow Bar and Safety Chains - etrailer XHD Non-Binding Tow Bar item # e84ZR
Base Plate Kit - Roadmaster Direct-Connect Base Plate Kit - Removable Arms item # RM-523198-5
Please note that this base plate kit will not work with the AT4X models with AEV bumper
Battery Disconnect - Roadmaster Battery Disconnect with Switch item # RM-766 for gas item # RM93MR for diesel
Supplemental Braking System - SMI Stay-IN-Play DUO Supplemental Braking System item # SM99251 or item # SM99243 if your motorhome has air brakes and the Roadmaster Stop Light Switch Kit item # RM-751495
High Low Adapter - The tow bar needs to be within 3" of level. If you measure the height of the inside top of the hitch receiver tube on your RV, and the height difference is more than 3 inches above/below the base plate tab height, you'll need a high/low adapter. I have linked a FAQ article that explains all this in more detail along with our selection of adapters.
Product Page this Question was Asked From
Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 7-Way to 6-Way Coiled Adapter Cord
- Flat Tow Wiring Harness
- Splices into Vehicle Wiring
- Diode Kit
- Universal Fit
- 7 Blade to 6 Round
- Roadmaster
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Base Plate for Tow Bar
- Search Results: base plate for tow bar
- Shop: Roadmaster Direct-Connect Base Plate Kit - Removable Arms
- Shop: Vehicle Tow Bar Wiring
- Video: Installation of the Roadmaster Direct-Connect Base Plate Kit on a 2024 GMC Sierra 1500
- Video: What to Know About the Replacement Breakaway Switch for Roadmaster Flat Tow Brake Systems
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Vehicle Tow Bar Brake System
- Shop: Replacement Breakaway Switch for Bright Way Trailer Breakaway Kits
- Shop: Replacement Breakaway Switch for Roadmaster Flat Tow Brake Systems - Qty 1
- Shop: Blue Ox Patriot Portable Flat Tow Brake System - Proportional
- Shop: Replacement Breakaway Power Cord for Blue Ox Patriot Flat Tow Brake System
- Shop: Specialty Recreation RV Shower and Tub Surround - 32" W x 23-3/4" D x 66" T - White
- Shop: Roadmaster Crossbar-Style Base Plate Kit - Removable Arms
- Shop: Suspension Enhancement
- Video: Roadmaster Battery Disconnect with Switch for Towed Diesel Vehicles Review
- Video: Review of Roadmaster Battery Disconnect Switch Towed Vehicle Flat Tow Brake System Diesel - RM93MR
- Search Results: battery disconnect switch
- Search Results: battery disconnect
- Q&A: How to Install the Demco Air Force One Flat Tow Brake System on a 2025 Chevy Silverado 1500
- Video: Flat Tow Ready - Install Blue Ox Battery Disconnect on 2024 GMC Sierra 3500
- Q&A: Looking For The Base Plate And Wiring For My 2021 GMC Yukon Diesel
- Q&A: Best Base Plate And Flat Tow Setup For 2025 Chevy Silverado 1500
- Q&A: Recommended Flat Towing Parts for a 2024 GMC Sierra 3500
- Article: Best Vehicles to Flat Tow Behind an RV
- Article: Flat Towing Package for 2007-2018 JK Jeep Wrangler and Wrangler Unlimited
- Q&A: Which is Better Roadmaster or Blue Ox Tow Bar
- Article: Trailer Wiring Diagrams
- Article: Must-Have Flat Towing Components
- Q&A: Recommended Flat Tow Parts for a 2025 Jeep Wrangler Sport Towed By A Tiffin RV w/ Quick Connect Air
Jerred H.
9/29/2025
Hey Howard, did you get a chance to set up your 2025 GMC Sierra 1500 for flat towing with the Roadmaster wiring kit and other parts? I'm curious to know how it worked out for you, as it could help others looking to tow their trucks behind a motorhome.