ID of dash switch/button on 96 Z3

I recently purchased a 96 Z3 and there's a switch/button on the instrument panel in a recessed area under the fuel gauge. The switch/button presses in and stays, press again and it pops out. I didn't get an owner's manual and I can't find a reference in a service manual as to what this is. Someone tell me what this is for?

Here's a picture of it.

http://www.chevelles.com/showroom/396guy/switch.jpg

Also, I have a Bentley Publishers Z3 Service Manual and it says that 96 Z3s have the battery under the hood while 97 and 98 Z3s are located in the trunk. Mine is in the trunk yet the VIN (and CarFax report) show it to be a 96. Late 96 model maybe?

Dale

foglights, work only when low beams are on.

That's it. Haven't driven the car at night 'till now so they never had the chance to be activated. Thanks!

Dale