1996 Ford Explorer XLT 4.0, Blower Motor
 

I am trying to figure out what is wrong with my heat and AC. When I turn on the blower motor no air comes out of the front vents on the dashboard but I get air from the top vents on the dashboard (windshield defrost vents) and the vents located on the back of the middle console that feed air to the back seats work perfectly also. Any idea what the problem could be? Are there different motors for different vents? If it were a fuse wouldn't the whole system stop blowing air?
TIA for any help with this problem

RE: 1996 Ford Explorer XLT 4.0, Blower Motor
 

So the blower motor is working? If I remember correctly all new heater vents are control by vaccum hoses, I thinking a vaccum hose is off or something has fail on a switch