No center vent air on my '85 300D. I took out the glove box and sides from the center console so that I can observe the actuators. When the fan is on (EC or AC) The actuator behind the glove box turns fully. There are 2 other actuators behind the center console. One has the usual vacuum line going to it, but the other one has 2 lines. One that connects to the end and the other hose connects to the side of the actuator. The one with only 1 hose will actuate and turn the flaps so that air is diverted to feet BUT ONLY WHEN PUSHBUTTON FOR BOTH TOP AND BOTTOM is pushed. If I push the button for bottom vent only, it will close the vent and air will ONLY BE COMING OUT OF THE SIDE VENTS. I hooked up my vacuum gauge to the actuator that has 2 lines to it and I don't get any vacuum on either line. I hooked up a good vacuum source to it while the A/C was running and it DID actuate but I still only had air coming out of my side vents. When I look into the center vents I can see some flaps but even when I actuate the actuator by hand those flaps don't move. I'm wondering if maybe I have a some linkage to those flaps broken. I would have to pull the dash to investigate further.
My questions are: 1) why does the 1 actuator work opposite to the way I would expect? It should divert it to your feet when you have the bottom only pushbutton pressed.
2) are those vents that I see thru the center vent console actually tied to the linkage of the 2 hose actuator? My thoughts were that maybe it is turning a vent behind the console that I can't see and the vents I do see will open by air pressure when air is forced thru them.
Sorry for the long post. Just trying to understand this a little better.
84 500SEL EURO 87K
85 300D 267K (and still goin' strong)