Couldn't find any clear reference to this one... Sort of a beginner question, I know...

W123 '82 300TD is the car in question....

What does the "Main" air flap do exactly? What happens when it's opened? And closed?

Next; the "fresh air/cabin air" flap utilizes cabin air when open right? So what's the advantage to having it closed? The reason I ask is because I'm considering rigging it permanently open (recirc). Is there any reason I shouldn't?

Thus far I've determined that my defrost flap is always open (obvious, judging by the condensation that's always on the windshield). Verified this one with a mityvac. The "foot" flap is a-ok! The center flap was all whacy, so I rigged it permanently open and plugged the vacuum line. I did the work on the center flap through the instrument cluster hole... quite tricky but it's done all the same.

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'90 300SE --- 173k miles --- (Odometer just stopped working!)

'85 Cali 300D --- 193500 miles --- (Second one) Sold Nov '10

'82 300TDT --- 236,xxx miles --- (My first one) Sold July '09

Is the question really THAT elementary? Dang....

__________________
'90 300SE --- 173k miles --- (Odometer just stopped working!)

'85 Cali 300D --- 193500 miles --- (Second one) Sold Nov '10

'82 300TDT --- 236,xxx miles --- (My first one) Sold July '09

When that actuator is "extended" you are in recirc. mode. When it is closed you are taking in the outside air and cooling it.

The only downside to rigging it permanently open in the summer time is longer cool down times when it is really hot out (inner city driving).

The original design was to have the flap move through a few different positions based on temp. IE: The flap is in the recirc. position most of the time, or a position of mostly recirc. on a working system with no vacuum leaks.



The rest... I don't know. I'm still working on the POS. It is like pulling teeth trying to find good info. on it. There are some good recent posts over the past couple days.

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AJ

1985 300D (SOLD)

Go to this post and scroll down to picture # 134.

http://www.peachparts.com/Wikka/W123Evaporator

#134 Recirc flap. When closed, it prevents 80% of the fresh air ( from the main flap area )from being recirc by the fan. When open it allows the fresh air and cabin air to feed the fan. That little cut out is the 20% fresh air that will be sucked in to the fan. That has to be there to allow the flap to move.

#135 Main air flap. Allows outside air to enter the car and be drawn in to the fan with cabin air. When the system is on, it is open, when the system is off it is closed

#136 Center flap. This is for the 2 center vents in the dash. Closed when heat is requested by the system. Open when cooling

#137 Defrost flap. Defrost opening. closed unless defrost button is pushed.

#139 Floor flap control. Allows the air flow to go around the feet.


For each button purpose on the AC control. Go to this post and scroll down to my explanation

http://www.peachparts.com/shopforum/showthread.php?t=173984&highlight=button+flap+control+dave

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

AH... most helpful. Thanks guys.

__________________
'90 300SE --- 173k miles --- (Odometer just stopped working!)

'85 Cali 300D --- 193500 miles --- (Second one) Sold Nov '10

'82 300TDT --- 236,xxx miles --- (My first one) Sold July '09

Again.... Thank you Dave!

__________________
AJ

1985 300D (SOLD)