Silly question here, and one that unfortuantely shows how infrequently I clean out my car...

I was vacuming out the front floor area this weekend (not too dirty either since it was professionally detailed when I bought the car in November) and noticed for the first time that there is a switch behind the accellerator pedal that gets activated when you stomp on the gas. What is that switch and what does it do exactly?

I would surmise that it either automatically downshifts the transmission or else changes some of the engine operating parameters such as fuel/air mixture.

Is this the ubiquitous "Go Button?"

it's the kickdown switch (#5)

http://bmwfans.info/original/images/4818_p.png

it's the kickdown switch (#5)

/go faster button.

When you press the pedal to the floor, it then down shifts the transmission into the best possible gear for power and does all the other things that other cars do when you floor it like opens the throttle fully and advances engine ignition timing.

It is really fun when you are crusing at highway speeds but I have found that with my V12 7-series that I spin tires more by getting the pedal as close to the button as possible but not touching it. Just some advice for a stupid way to waste money on things like gas, tires, and weak links in the drivetrain.