What is this button?

[Jwigz]

BMW_ interior.jpg

Can anyone explain what that button does. I press it and no green light shows up like on the other side. I feel like it is the heater, but the heat only blows near the windshields. I know on the other side is the max a/c and that blows directly in my face when I turn it on by pressing it in.

[Jwigz]

http://www.m3post.com/forums/showthread.php?t=823132

[trohde78]

It only works when the car is turned off (not running). If the engine was warm enough it will allow the heater to run while the car is not running for up to 15 minutes.