please help...i have searched the archives and have not found what i need. 89 750 il when i run the a/c on the cold level any setting(63-78) it does not blow cold air. the two front vents are warmer than the one on top and two sides. i have had the system flushed, pressures are good,im told from mechanic, have replace the heating element, fan clutch, engine thermostat. with the unit on coldest setting, air from vents still comes out about 80-87 degrees. any help would be appreciated as it is somewhat of an embarrassment to drive around a beautiful car and get out with shirt stuck to back and sweat POURING off.