My passenger-side auto switch for the A/C will turn itself off every once in a while.

On the I-drive screen at the bottom there is the left and right fan displays that always say 'Auto'. What will happen is as I am driving the passenger one will switch to the white bar that controls fan speed (the green light on the Auto switch actually stays on) and the fan stays on whatever speed it happened to be on when it switched. I have to press the Auto button again and it will resume working properly - sometimes for 5 minutes, sometimes for a month.

I can't reproduce the problem and it is not caused by bumps or anything. It happens whether it is heating or cooling the car.

I've had the dealer look at it twice and they said they couldn't reproduce it and everything tested out fine. Ironically, both times they looked at it, it worked right (stayed on Auto) for a few months then started acting up again.

If anybody has had a similar problem and figured out how to fix it, I would appreciate it.