Using SMI Air Force One Braking System on 2016 GMC Canyon Diesel with Battery Disconnected

Question:

The owners manual tells me I need to disconnect the battery when flat towing my 2016 GMC Canyon 4X4 so Im considering the purchase of your automatic battery disconnect. This truck is a DIESEL and I will be using the AirForceOne brake actuator. The question is will the brakes work when the battery is disconnected? On a gas vehicle the brakes are activated through the vacuum booster and I assume the brakes on the DIESEL are electrically assisted.

asked by: Randy S

Expert Reply:

I took a look at the online owner's manual for your truck and was able to verify that the negative battery cable should be disconnected when flat towing the truck. With that being said, the Roadmaster Automatic Battery Disconnect with Switch # RM-766 referenced in your question is not recommended for use on diesel engine vehicles like yours. This is because with the high compression ratio of diesels the engine can surge up to 10 times that of a gasoline engine at start up and potentially cause the solenoid to fail.

I spoke with my contact at SMI regarding the SMI Air Force One Supplemental Braking System # SM99243 on your GMC Canyon with the diesel engine. He did confirm that this system will still work great with the battery disconnected on your truck. As you mentioned, it's going to take a bit more mechanical force to apply the brakes since there is no vacuum assist, so you will simply need to use the Hydro-Boost Kit that is included with the system.

You can take a look at page 21 in the attached installation manual for details on this kit, which is specifically designed for vehicles like yours without vacuum brakes.

expert reply by: Chris R