Let's try this again. Help!! A/C problem

[85 500sel]

I need to reiterate my ac problem. My a/c will only blow warm air. I took it to my indy and they topped it with freon. It got cool, but later on in the day it got warm and has been warm every since. They checked it for leaks and they found none. Before they charged it the clutch would not engage. After they charged it the clutch engaged. Now the clutch does not engage. If there is no leak where is the freon going?. Also, the auto fan switch will not engage. When I press it the spring will not hold. I have to run it on low or high fan. I read the diy links about the monovalve and it does not seem to apply to my problem. What could be some other culprits? Could it be the compressor? I need to be able to tell my indy some things to try. I hate to pay the big bucks for a compressor if I don't need to. The car is a 1985 500 SEL. Please advise. Thanks in advance.