My 2001 Ford Focus I hear air blowing really good but nothing coming out

well to start out you vent doors in the dash are vacuum operated and sounds to me that you have lost the vacuum so you need to find a diagram for the system, but as starting point in the engine compartment look for a hard black or gray tube usually about 1/8 to 9/32 in diameter coming out of the fire wall it could also be raped in a wiring harness as well and fallow it around and see if it's broken or disconnected. if all good there go a check the dash control connection for vacuum you could have a bad unit.. good luck hope this helps