Chevrolet Repair: astro van air conditioning, check fuse, astro van

Question
The air conditioning unit is blowing only throught the window defrost vents on top. No air is coming through the front vents, also nothing happens on the High position. This switch has already been replaced and there wasn't any change in the problem. It's an 1998 Astro van

Answer
Look for the vacuum "ball" with 2 vacuum lines running to it, under the hood, sounds like the large hose has fallen off, if not possibly the main vacuum switch (master control) has gone bad, on the high blower, check fuse, then high blow relay, Good Luck!