ac wont blow cold,but pressure is fine

hi i have a 98 blazer the other day was driving and the alternator went out all the gauges went dead battery was drained,broke down soon after that.so i put on new alternator charged battery up it started right up but no ac just blows hot air compressor kicks in i checked the pressure its ok,it blows hot air when the vent is open.deos anyone have any ideas.
thx for your help

Did you check the compressor? OR maybe there is no refrigerating liquid left!