Mercedes: 1980 Mercedes 300CD climate control., vacuum system, mercedes benz

Question
Just purchased 1980 Mercedes 300CD.  The defrost works on the climate control, but nothing else does.  Where do I start?  I see that there are so many expensive parts associated with the AC and climate control and I do not want to buy one of each.  This is my first Mercedes and diesel.  Please help with any suggestions.  Also the sun roof does not open.  I can hear the motor, but nothing happens.  I can not figure out how to get to the guts.

Answer
Wow, your question helped me find a new product for our older Mercedes Benz!

http://catalog.mercedesshop.com/item.wws?catpk=&sku=227550999

To answer your question:
Defrost is default setting = system failure drops it into defrost.

Start diagnosing your vacuum system = vacuum pods and valves.

Cut and paste these links for many pages of climate control DIY help.

http://www.mercedesshop.com/Wikka/DoItYourSelf?cookieID=1JH0K424Y1KP17LOAJ&sourc...

http://www.mercedesshop.com/shopforum/showthread.php3?t=105297

http://www.mercedesshop.com/shopforum/showthread.php3?t=86871