94 S10 Blazer AC blows from floor and vents

Regardless of the control setting for AC (max, normal, bi-level) cold air blows from the floor discharges and the vents. The temperature seems cold enough. I also notice that when the vent only setting is used, air also blows from the floor discharge and vents. Please give me your thoughts.

Thanks for the help.

Mike Simone
1994 S10 Blazer, 4.3W engine, 177,000 miles