SL55/63/65/R230 AMG: Air conditioning interior air intake vent - Where is it?




Where is the air conditioning interior air intake vent?
Also:
There are two buttons positioned BETWEEN the center air vents, BELOW the hazard button and lock/unlock buttons, and ABOVE the 3 AC vent controls.
What do these buttons do?
Can anyone link me to HVAC instructions? It seems like this car can do some HVAC features that I do not know about.
i have no idea where the air conditioning recirc air intake is. my guess would be under the dash on the pass side.






