Battery Drain Issue When Flat-Towing 2012 Cadillac SRX Using Air Force One Supplemental Brake System

Question:

I recently installed an Air Force one braking system on my car, including wiring that was needed. While towing the car from Florida to Pennsylvania, I experienced the battery going dead on two occasions. The Air Force One is completely dependent on the coach and has no draw on the towed vehicle. The battery in the car was replaced 2 months ago and checks out fine. What is causing the battery to go dead? No one seems to know.

asked by: Allen B

Helpful Expert Reply:

Ironically we just had the same issue with an SRX. The problem was that when installing the Air Force One # SM99243, one step was not done and caused the battery to go dead. When installing the unit in the SRX, the brake pedal has to be moved to the forward position closest tot he driver seat. If it is not, when the unit is installed and tries to adjust itself it applies just enough pressure to make the brake lights go on and run the battery down. It may be something not noticed with the driving but happens just the same.

I have attached the instructions from the # SM99243 installation instructions that explain how to deal with adjustable brakes on your vehicle.

Step 6: Mount the Cylinder
Special attention must be given to vehicles with adjustable pedals. Check for
proper clearance in all positions. When adjusting the cable, be sure that the pedals
are positioned closest to the driver’s seat. This will allow normal operation of the
adjustable pedals. Be sure to return the pedals closest to the driver’s seat when
preparing to tow, or the braking system will not function properly. As an option, the
pedals may be moved to the desired position and disabled. Do not depend on the
fact that “no one moves them.”