Flat Towing a Diesel GMC Canyon with Air Force One and Battery Disconnect Explained
Updated 04/16/2026 | Published 04/10/2026
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Question:
Question on Demco AF1 Breaking system to flat tow for 2026 GMC Canyon, Best I can tell the truck does not use Vacuum on the brake system, so what is the vacuum connection for? and since the Battery Ground is disconnected do you go about powering the electronics differently than the Video not sure how it will work with the Ground to the Battery disconnected.
asked by: Robert
Expert Reply:
Hi Robert,
You’re absolutely right to be thinking carefully about this, because getting the braking system and power setup correct is what keeps everything working safely when you’re towing. I was able to confirm from your truck’s owner’s manual that the negative battery cable does need to be disconnected for flat towing, so you’re on the right track there.
The good news is that the Air Force One system part # SM99243 will still work properly with the battery disconnected on your truck. I checked on that specifically, and it’s designed to handle setups like yours. Since your Canyon uses a hydro-boost braking system instead of vacuum assist, the included hydro-boost kit takes care of that difference so you still get consistent, reliable braking force when you’re towing. I have attached a photo of what to do with the vacuum port or connection.
On the electronics side, most lighting options, including the Roadmaster part # RM-15267, pull power straight from the motorhome, so disconnecting your Canyon’s battery will not cause any drain. The Air Force One system is set up the same way and also draws its power from the motorhome, which helps keep everything simple and self-contained while you’re towing. The only time you would need to consider adding a charge line like the part # RM-156-25 is if the lighting option uses the Canyon’s 12 volt power or you run another accessory while it’s being towed, since that would slowly draw down the battery once it’s disconnected. Otherwise, both the braking system and most lighting setups won’t rely on the truck’s battery at all. An example of a lighting option that uses 12 volt power from the towed vehicle is Universal Magnetic tow lights part # TL21RK.
I can also get you setup with a quick battery disconnect so it's you're not disconnecting battery each time. Is your truck a 4,6, or 8 cylinder? Or is it a diesel?
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Product Page this Question was Asked From
Demco Air Force One Flat Tow Brake System for RVs w/ Air Brakes - Proportional
- Flat Tow Brake System
- Brake Systems
- Proportional System
- One-Time Setup
- Vehicle Battery
- Fixed System
- Power Assist Brake Compatible
- Air Brakes
- Indicator Lights
- Demco
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on Flat Tow Brake System
Stacey
4/16/2026
I purchased the Air force one towing package for my Lincoln. I do not need to disconnect my battery but the system gets all its power from the motorhome. I also bought the magnetic tail/stop/turn signal light system to bypass the Lincoln's wiring system. Everyting works perfectly and we are very pleased with not only the products but the way Etrailer shipped and answered all the questions before purchase. A Great company to deal with.