You need to go to a car parts store, and get a repair manual for your car. They cost about $16.00
I had this problem before on a ranger you have to pull the dash board out and it will be right there.
The selector mechanism needs repair or the doors inside the vent are jammed.
I have a 1999 VW Passat and had the passenger side dash lights go out. I had to get new vents for that side believe it or not as they are connected in some way.
The flap that directs sir to the selected vents is jammed or broken...or the switch that controls it is.
the middle vents only supply air from the ac unit using a separate in dash fan. the floor and defrost vents come only from the heater
google astrosafari van repair and you will find a lot of info on how to repair/replace your vacuum lines and valves
No air flow? Check for vacuum leak either under dash or at engine compartment Maybe bad vacuum diaphragm under dash Maybe bad selector control
Shut the car off and get out. Something is broken and if its producing smoke, it could catch on fire.
How to change dash lights on a 95 Ford Ranger?
how do i reset the sensor on the instrument cluster on a 1984 corvett?
some thing is probley cloging the vents take it appart and ckeck.