My car wont blow air outof the defroster vents. on 1997 Buick Park Avenue

I understand the idea of dampers and actuators. Is there a drawing available that shows the different dampers and their locations.

Asked by for the 1997 Buick Park Avenue
you may have a small vac leak under the hood at your vac ball,start there and ck hoses thru firewall to controller
where is the vacuum ball?
under hood on pass side inner fender i believe. its a 3" blk ball with 2 vac hoses attached to it,follow the hoses and look for breaks or cracks