A similar thing happened to me, but the HVAC system went on full blast A/C Auto. I was driving through city and was in a rush to go to the hospital because I was running late. I was in the right hand lane and moments too late, there was a large dip in the road, almost like a man-made pothole due to construction to install a drain or something, I ran right into the pothole. It was unmarked, no construction sign or "Right Hand Lane" closed sign... I cringed with the sound that car made hitting that dip in the road. (like a loud BANG bottoming out)

Car was fine and still got to the hospital a little late, but I was wondering why did my A/C went on automatically. I thought the shock the car went through made it short a wire or something in its "brain"... Until I realized yesterday that sometimes my hand hits the "auto" button on the steering wheel.