I have a 1993 Camry LE | 4 Cylinder 2.2 Litre | 118K miles. There is no air coming from regular vents (on face) in the dashboard although there is air coming from the windshield vents and underneath (on legs). I tried looking up for this problem and found that I need to check the Vacuum supply from engine to the heater/AC controls. Is this correct? If yes, how can I check it? Also please let me know if there is something else I should check.

When I turn the knob so as to expect air from regular vents (on face) the air goes to either the windshield or legs.