Hey cal thanks for the pictures. yes I replaced those parts today....unfortuantely when i went to replace the pressure switch with the 2 pigtail wires, i was sprayed in the face by something......mostly air and some grren stuff, but i still replaced them. same thing happened when i replaced the thing on top of the valve...i guess the a/c cutoff switch on top of the cylinder head....hot water/coolant sprayed out everywhere. so i know how to replace the lost coolan/water, but what do i need to do to replenish the stuff that came out of the receiver/dryer?

Well, you learned something yesterday when you were sprayed in the face. That was your 134a freon and compressor oil. You have effectively drained your a/c system of its vital fluids. This is going to a le$$on in auto mechanics. I think Larry Bible might be able to give you a primer in what you did wrong and how to address this issue but suffice it to say that you are back to square one.
Sounds like your vacuum pods are out or going out if you get air coming out randomly from dash and wiindshield vents.
Also, replace your monovalve, it is obviously bad. That's the thing you blocked off.
Next, you have to recharge your a/c system to get the proper level of refrigerant and compressor oil. Without either of these, the sytem will not cool and you could damage your compressor.
If you don't have a manual, get one. You could seriously injure yourself if you are don't know what you are doing and taking things apart. If you don't posses the "3 T's"... Time, Tools, Technical knowledge, then you need to pay to have it done. "Repairing" this car by throwing parts at it is false economy. At least pay a professional to diagnose your problem and then you can attempt a repair yourself.
Good Luck

yeah, well the parts have been replaced so I at least know that they are done. I am at a service station now having the ac evacuated and recharged.

ok so here is the update, I took it yo a service station and they evacuated and recharged the system and now my ac is ice cold. thank you all for your help and input.

WOW! just clocked my a/c as being -50 degrees! I'm really excited about this. I haven't had a cold a/c in 5 years!

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1990 190E 3.0L