Vent Problem

Hello, well I was going to get rid of this car, but I just can't seem to leave it. I own a 2000 V6, Now I'm having problems with my vents. . .No matter what setting I put the heat or ac on it won't work it only comes through the defrost. Is there some sort of module that needs replacing? Also the rear defroster does not work either, are these problems connected?

Well I figured out the defroster part, It was just a fuse but I played around with the fuses for the heat and ac and its still a no go I can't get anything through my vents? Does anyone have an answer to this??????

Maybe a vacuum leak in the dash or a stuck actuator not allowing the air flow to change directions.