I will conquer the Automatic Climate Control System II

[JasonP]

I have accepted the challenge.

So it is written.
So shall it be done.

[1980sdga]

You can do it!

Post what is/isn't working now. TAKE YOUR TIME!  If most of the vacuum lines are intact and haven't been worked on before then LEAVE THEM ALONE!  If you start pulling/swapping lines you can get into trouble and make new problems. Easier to find any leaks without manipulating  too much stuff and fix them one by one in a very systematic manner.

You'll need a mity-vac to start with. Another thing I found VERY useful was a motorized vacuum pump which allowed testing of the vacuum system without the engine running.

Some good resources:

https://s3.amazonaws.com/sspublicweb/mercedes/Mercedes+116+Climate+Control+Service+Manual.pdf

https://s3.amazonaws.com/sspublicweb/mercedes/83-604+climate+vacuum+diagrams.pdf

[Big_Richard]

.

[JasonP]

Thank you! And thank you so much for those pdfs! All I have right now is a multimeter and an engineering background.

Right now, the system blows lukewarm air when on DEF, but then has an electric buzzing sound when on any other function. I have run the system on cold (20-30 F) mornings, for about 5-7 minutes, so I am not sure if that is enough time for the air to heat up.

The previous owner told me that the heat works, but nothing else works. The dashboard unit pushes in when I push a button (indicating it is loose and has been pulled and tinkered with), and the glove box is missing, with a small rectangular metal box dangling in it's stead.

That is far as I have gotten. I will keep you all posted!

[jbrasile]

I second Jon's suggestion, try to leave the vacuum lines alone if all looks ok. First thing to do is check for vacuum leaks using a hand held vacuum pump. Begin with the fresh air element under the dash, passenger side sort of behind the glove box, you can access it by removing the covering panels under the dash. There is a blue/white actuator and a pink one, test both, usually the blue/white has a leak, if so it will need to be replaced.

Then go for the vacuum pods behind the center vents, you will need to remove the glove box liner (which you mentioned you don't have anyway...) the center vents and their molding which has a rubber boot which attaches to the top of the a/c box. The pod near the passenger is the center vent control, it sits horizontally  and has only one vacuum connection behind it, the one near the driver sits vertically, controls the defrost flaps and has two connections, one at the front one at the top, test both. It is possible to access both pods without removing the center vent assembly if you have very flexible hands..... taking out the instrument cluster will give you a little better access to the def pod as well.

I will leave it at that for now, let us know how it goes and will go step by step.

Tks,

Joe

[scraf]

All I want is some heating in the winter.

Joe, your last post reminded me why I haven't made much progress the last four years.