You don't have vacuum to the climate control. Look for a loose line (the green ones are climate control) in the engine compartment or under the dash. There is a restriction orifice (yellow or white "but connector") in the line or at the connection to the main vacuum line that goes to the brake booster -- these can get clogged, reducing the vacuum to the climate control.

The best way to check is to get a MitiVac hand pump and try pumping the green line down by hand -- if it won't hold vacuum, you have something seriously wrong under the dash, it if does, plug the Mitivac into the other end of the line with the engine running and see what kind of vacuum you get. If you get good vacuum with the hand pump and the flaps still don't work, you have something wrong with the control unit (very rare). At worst, you have a weak vacuum pump that needs work or replacement.

I had the same problem on the 300D recently -- turned out to be the turbo recirc and EGR actuators are leaking badly -- the car still shut off fine, but there wasn't enough vacuum at low speeds for the tranny to shift properly or for the climate control to work. I plugged the lines until I can get replacement acctuators.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!