What controls this flap?? 1983 300SD Ventilation system
 

I tried to post a pic, but the upload failed, so I'll describe it the best I can.

On the driver's side, with the duct work and kick panel removed, there are two openings in the side of the unit. The lower opening provides heated air to the driver's feet. Inside this opening, there is a vertical flap. There is a vacuum element to the left that functions properly and opens and closes a hidden flap somewhere above it, but I don't see the mechanism that moves the visible vertical flap in the lower opening.

What is the name of the flap and what is supposed to control it?

Thanks in advance!

It's the same on the 84 30SD. I open the flap and it seems to just be blown closed. Now all the hot air comes out at the top.
I have the same question.

Not sure if this will help, but if your issue is no floor heat, perhaps a failed wrist pin on the floor flap may be the culprit. Was on mine.

The vacuum element on the LH side of the console is for the Diverter flap.

I believe you are looking at the footwell flap. The vacuum element for it is behind the radio and Pushbutton Controller.

This section of the FSM should help you out: Mercedes-Benz 126 Service Manual Library

I think I have located the problem. The vacuum actuator is working, the horizontal lever moves, and the passenger floor flap opens and closes. I think my wrist pin is broken as toomany MBZ suggested.

Now.....Is there an easy fix?

Thanks!

Years ago I used a spark plug to wedge the door open, so far, so good. I did tie a piece of string around it, just in case it fell inside somewhere.