Might just be coincidental. Check vacuum hoses for leaks, cracks or spongy feeling lines under the hood. Replace as needed. Worst case scenario - vacuum lines are broken/came loose behind the dash or the A/C & heater "switch" has dried out grease or broken internals. A combination or any one of these items mentioned will lead to your windshield getting more air than your face.
Also of note - check the little "ball" attached to the driver's side of the hood. There is a check valve in the line that joins it up with other vacuum lines. If that goes, it may cause what you are experiencing. But either way, inspect and replace hoses, valves, and orifices before you go pulling out your dash.
Also, spend the $10~$14 for a Chilton's book for your make/model year. It will give you the details of where to look to find all of your hoses and miscelanous related components of your vacuum circuits. Good luck!