Lack of air from vents

[Saiboot]

Ok, interesting problem: When using my air, the blower motor is blowing air, but nothing is blowing out the main vents. Floor and defrost vents blow fine, and they are the only ones. I traced the yellow vaccum line from the control switch over to an actuator under the gauge panel, and if i push it in, the vents will start to blow air. obviously this is some kind of door to let air in, but my question is, why is that line getting no vaccum? could it be the switch, or might i not be getting vaccum to the entire control system, and how can I tell? if i turn off the car & then turn the knob to OFF from MAX or otherwise, I hear vaccum being let off, but now nothing...any ideas?

 

[RustBucket]

did you take the yellow line off to see if there really was vacuum or not? Those dashpots have a diaphragm inside them that can age and leak. You've at least determined that its not stuck, but you'll still need to find out if the problem lies with the dashpot or the selector switch. Pull the line off and set the selector to MAX A/C to see if you get any vacuum on the line. If not, check the selector.