How do I get at all of the ducts and flaps and doors, etc, that control where the air goes, and how do these operate? By vacuum? I can press every button (except for 0) on the dash, and airflow does not change--temp wheel seems ok as does fan speed--but cannot get the airflow direction to change. Also, don't believe recirc is actuating anymore, although it lights up. I just don't hear it "come on" like it used to. No A/C out of center vents--but it will come out defrost vents and side vents where it is currently stuck. You guys seem knowledgable here...

Thanks

__________________
________________________
2002 Mercedes-Benz E320 4Matic
1995 Mercedes-Benz E320 Wagon
2005 Land Rover LR3 V8 SE
1999 Audi A8 4.2L quattro