Why won't air blow out of my vents?

[Johnny Fort]

Hey guys, just checked my car at lunch and noticed something funny. No matter what setting it is in, max ac, norm ac, vent, floor, defrost, or whatever else, the air comes out of the floor and defrost at the same rate (max isn't faster than normal ac). So basically, it seems that that switch/dial does nothing to alter the air/heat. The only difference is that it turns off when I put it to off. Now I'm really confused. (and starting to sweat coming home from work!)