I decided to do a little bit with this last night... Figured I would look to see why the air never really changes from blowing out from all vents all the time... I figured I would do the checking on the different pods to see which are bad so I could order them prior to taking the dash apart. I pulled the glove box and checked the various vacuum lines with a mity-vac. Now I am wondering which lines go to which pod?

Here is what I came up with:

Line coming in from the top - with engine running has 10" vacuum - Is that correct? I would think it should be higher.

With engine off, I used the mity vac to see if each would hold a vacuum.

1 - zero
2 - holds 5" only
3 - slowly leaks down
4 - holds 25"
5 - holds 25"
6 - only holds 5"
7 - holds 25"

With the engine running, if I push the various buttons I can hear the vacuum manifold click but nothing ever really changes as far as air coming out the floor only or defrost, and air always comes out the dash vents (all).

__________________
05 SL600 75K
87 MB 560SL 119K
87 MB 300D 180K
83 MB 240D 110K
64 1/2 Mustang
74 Monte Carlo 32K
75 Fiat 124 Spyder
16 Equinox
15 2500HD Silverado