Air only blowing through defrost vents

I own a 2002 Ford Ranger recently the air stopped coming through my front panels, I mean it justed stopped. Instead the air only come through my defrost vents. The blower controls work fine, the temperature dial works fine, but the dial that adjusted the air for the floor,windshield,and front panels doesn't do anything. Where ever I turn it to it always just blows out the defrost ducts. Normally I wouldn't care, but I live in Arizona and it's hot right now. I want the cool air on my face and body not the windshield. If anyone has any ideas or how to manually move the damper I would appreciate it. P.S. I checked the various fuses and ducts for blockage, they both were fine.

You probably have a vaccum line disconnected from the vaccum motor that controls the mode door in the plenum. Or a vac line elsewhere is disconnected. When this happens the defrost only works. This is a safety default feature in case you lost vaccum. That way you would still have defrost for cold weather. OR in the case where the mode door is controled by an electric actuator , it may be disconnected or bad.

i have a 97' ford ranger and it did the same thing, my boyfriend checked it out & my vacuum hose was disconnected

I am not sure where the year comparison starts but the blend door will get worn at the pivot point and you either take apart heater to fix (crummy job) or make this in vehicle repair that I ran across on the net when doing a search for the same problem. Try a generic web search to find that repair and I will look for the one that I had found.Our 99 ranger is the one we worked on we worked through the glove box hole. I think you take off the auctuator on top and look in with a mirror to see the hub is cracked, and then a repair can be made by drilling and inserting a pin .I don't remember exactly so I will look for it.