W203 Climate Control Problem

[pkor]

I've noticed that in my car air keeps coming into the leg compartment, regardless of the climate control settings. It weakens a little when I set it for the center vents, but still strong enough. On long trips, with AC on, it feels qiute uncomfortable.
I went through links in the DIY section and read about vacuum pods. I pulled one of the under-dash panels on the passenger side, but I wasn't able to identify them. The complete lack of repair manuals does not make this any easier.
Any ideas?? Thanks in advance!