Just checking that flap behind the glovebox to ensure that it's closing all the way (AC doesn't seem _quite_ as cold as it should be (R12))

Anyway, it's working like this.

With the ACC button in the OFF position (Circle button), the flap is closed.

With the VENT button on, the flap closes.

With the AC on, the flap stays closed. With the AC on and in the MIN position, it stays closed.

Is this right? Does the flap being in the open position allow fresh air in? And...when the AC is in ON but not in the MIN position, shouldn't the flap be open slightly, or is this flap an 'all-or-nothing' flap?

On a side note, I was looking for the roof temp tube that supposedly runs down and behind the glove box (the one that rots). Didn't see anything that looked like it. Is it back there?

Attached Thumbnails

 

__________________
Chris
1985 300SD - 'Grace' (198K mi.)
2018 Honda Civic Sport
2018 Honda CRV LX
2010 Honda Fit Sport (RIP)
2013 Honda Accord Sport (Sold)
1996 Lexus LS400 (Retired)
1995 Ford Contour SE (Retired)
1976 Porsche 914 (Sold)
1972 Datsun 240Z (RIP)

The flap ought to open when its hot out and you turn on your A/C. Or, if you push the recirculation button (the one with arrows going in a circle - a light will come on too).
The ought to slowly move open. As you probably already know, this would recirculate cabin air- with the intent of cooling off the cabin quicker. You can also activate the switch, if you are driving by some place smelly (like a sewerplant) and want to avoid smelling anything noxious, or avoid getting blamed for emitting noxious odors.

If the flap does not move no matter what you do, your next step would be to see if the actuators need replacing. The rubber diaphragms deteriorate after many years, and no longer respond to suction. (I would hate for that to happen)
Anyway, you can remove them by twisting them a few degrees, and pulling them out of their harness. (be sure and remember which color vacuum tube goes where) They don't need a whole lot of suction to determine if they work or not, so if you want, you can just hook up a piece of vacuum line and suck on it to try and make it budge. If all you get is air, then the diaphragm is broken/torn. Buy replacements. Don't worry if only 1 type is available....the vacuum elements are all the same, and interchangeable with whatever actuating lever belongs to it. (at least that's what I have found so far)

btw. There's another actuator to the left of the glovebox opening - it sits upright...might as well test it too, while you are at it.

Have fun!

-Larry

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

There's no recirc button on this car. I'm still not clear on what position the flap is in.

Flap open - Pulling in outside air?
Flap closed - Recirc'ing cabin air?

The actuators _do_ move fully open and closed...just not sure what the flap positions do.


Chris
'85 300SD

Open = Recirculating

(don't stick your fingers in there too far, or you will meet the fanblades)

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

So then when I turned on the AC and put it in the MIN temp position, that flap should have opened back up, hmmmm.

Wasn't doing that.

Chris
'85 300SD

http://business.baylor.edu/Richard_Easley//autofaqs/recirc.htm

This has info about your problem and how to fix it.
-Joe

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

The recirc button became available in US 126 cars starting in 86.

Per the CD manual:

With the engine off, the flap is open allowing outside air into the cabin. ACC setting doesn't matter.

With the engine on and the ACC off, the flap should close completely. Off is the only mode that will effect full recirculation.

In defrost mode, the flap is full open.

In any non-heating mode, the flap is 80% closed except for some situations in EC mode when it's 20% closed.

Joe is right - the Richard Easley instructions will guide you through deciphering if the flap is not closing enough because of lazy actuators.

Sixto
95 S420
87 300SDL

Well... I guess it depends on which side you are standing, in order to determine if the flap is open or closed. Especially since once it is closed to the outside, it is open to the inside.

Looking at the pictures (taken from inside the car-through the glove box) I would say that the flap in the picture is "open" (or really close to it) and that it is in recirculating mode... - that is assuming that the engine is running, and you have the A/C on.

I have had mine apart on the 88 SEL and when it is recirculating the flap is open, and is definitely sucking in air from within the cabin.


Hope this clarifies what I was trying to say earlier

-Larry

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

I hope it clarifies what I said too.

Sixto
95 S420
87 300SDL