2004 Mountaineer Blower works, but no air thru vents
 

Is there a part that I need to replace so that I get air through the vents?
No matter which vent button I push, even though the blower is on and the fan control speeds up/slows down the blower just fine, no air comes out of any vents.
Does this mean there is an exit door that is stuck closed?
this 2004 is in perfect shape otherwise, with only 79,000 miles. / Thank you