what is Actuator for Fresh Air Flap

I don't know BMW well but what you describe sounds (like a lot of new cars) the heater controls operate a motor electrically or by vacuum to mover the heater control flaps withing the heater box/ The flaps are moved by an actuator/motor to direct air to defrost, the floor or center vents. Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info. There is also a company that independent auto repair shops buy their information from that the same information inexpensively to do it yourselfers. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online