A/C woes

89 300E. I have had hundreds of dollars of work done to my climate control system. Currently, it has a fresh charge of freon and a new a/c relay unit. And yet it still doesnt work well. I get nice cold air on low but if I bump it up to the automatic or high setting I might as well be using the vent function found on cars without A/C. Any ideas?
Ryan

[mbdoc]

Whenever you select A/C mode on climate control (a/c/c) the fresh air is intake is closed off & scoop air flap closes heater core off from eveporator. Sounds like these vacuum flaps aren't working. Have repair shop check to see if vacuum system is working. Also heater valve might be leaking & allowing hot water to flow thru h/core.