I'm about to order a new climate control unit but before I do, I'd appreciate your thoughts. (I did a search.) I have a 1988 420 SEL with about 130K miles. The air conditioning doesn't cool. My mechanic has checked all the refrigerant-circuit elements and the refrigerant pressure and all are working as they should. He believes the air mixing door inside is not opening properly for controlling the air temperature.

I trust this mechanic's diagnosis because he has repaired a number of problems with my SEL.

The air conditioning cools slightly, but not enough for our 100+ temperatures. I've read that the vacuum actuators may be bad, and I would order those but I don't see that part listed on this site. I need to get this fixed as soon as possible because this is our daily car, and my wife doesn't like to sweat.
Jerry