Chevrolet: heater/AC vents, chevy astro, vacuum hose

Question
Keith, I have a 98 Chevy Astro.  No matter what setting I use, vent, defrost, or floor, all of the air comes out the top (defrost).  Is this an electrical problem or is something stuck so that the air will not flow through the other vents?  Thanks in advance.

Answer
Hi Perry, The heater controls are controlled by vacuum. It may be as simple as a vacuum hose off or broken. You have to find the supply line to see if it is broken or disconnected. And also check for a blown or missing fuse, some vans have an elecric vacuum pump. I hope this helps you. Thanks, keith.