Air blowing out defroster only

I had the same problem. Air would not blow out the HVAC vents on the dash or at the floor. I found this post and looked on the side of the engine (drivers side) and found a dangling hose. I had to search to find the connection spot at the bottom of the engine block, way back and behind things. I connected the hose and everything worked. Cost to fix -ZERO. Thanks Rich from Illinois.