ac blows cool but not cold. blows at about 68 degrees. ac tubing under hood does not get cold. any suggestions?

 

Usually the system is low on refrigerant.
Do you hear any clicking from the air conditioning compressor magnetic clutch? If you do , chances are its only low on refrigerant. If you don't hear any clicking of the clutch engaging and disengaging , it is either totally empty or you have an electrical problem. You can purchase a kit at many auto stores and add the refrigerant yourself. If you decide to do this , let me know and I will try to help you so you don't get into any trouble, its not difficult.
hanky