Air vents not working properly
 

My air vent only seems to blow air on the basic setting, at your upper body. It goes on and off just fine and the hot air still works.

The defroster, feet, and the combination settings have stopped working.

I've taken apart the console and looked at the switches and knobs and nothing seems worn out. What should be my next move? Thank you.

2001
2.6 L
4 Cyl
109,000 K

vacuum leak