Hey I recently changed my sparkplug wires and I dont remember if they still worked right after this but now my ac is not blowing through the vents. It will come out the bottom and out of the really small ones up top by the windows but not out of the regular vents.

 

If it mainly blows out the defrost and floor, you probably disturbed the vacuum line that feeds the mode switch on the dash. It is fed from the intake manifold and goes to the check valve by the a/c evaporator. The check valve is easy to crack, but it is a cheap part to replace. Try looking those places first.