GMC Repair: A/C-Heater, gmc safari, vacuum leak

Question
I have a 1999 GMC Safari Van.  When you turn the A/C or Heater on it doesn't blow out of the vents.  You can hear the fan blowing, as you adjust the speed you hear it blow harder or softer accordingly, but nothing comes out.   It will only blow slowly out of the defroster vents no matter what setting it is on, this goes for the heater as well.  The rear AC works just fine. What would cause it to stop blowing to the other vents?  And how can I fix it?  Thank You

Answer
You have a vacuum leak. All you can do is remove the engins cover and look for a broken vacuum line and replace it. It is normally the one that crosses the top of the engine.


I am sorry that it took so long to reply, it has been very busy around here.