Airconditioning issues

[stardy11]

Hello,

My 1997 c280 is having AC issues. It is now blowing the cold air out the side vents and the defrost vents at the base of the windsheild only. It does not switch between the various different vents. Another thing that I bet is related is that the AC runs cold for a bit, then it starts to run warm...like the AC is no longer on. Any suggestions? And also...any ballpark estimates ($20 bucks or $arm /leg?). I will not be doing the work myself. It will be either an independant shop or a dealership. i would just like to know what I am up against. The car did have a warranty until June so the dealer WAS very friendly to me.

Thanks, in advance!