Does your car have an automatic climate control system? (Horizontal
"window" screen with up/down arrows at its ends.)
If so, driver and passenger may set a temperature for their respective
The fan speed button, when set to 0, shuts down the system.
There's an air distribution mode button whose selection is pictured in
The system is set to "automatic" mode when the small red light(s) on the
outermost tough pads are glowing.
If your car's system differs I suggest you order an Owner's Manual from
M-B dealer as there will be other questions as well.