A/C Problem

I turn on the dial to blow hot/warm air and it blows hot/warm air..soon as the engine has warmed up. My heater works fine.
I turn the dial to cold air, because its startin to get a lil hot in oklahoma, and the unit blows air very very slightly through the vents *note, this occurs even when I have the air on max flow*
The air simply doesnt blow through the vents and isnt cold.
The compressor has been replaced in the past so it cant be that, anybody have any suggestions, ideas, answers, please let me know
Thankz

check for loose vacuum lines under hood