Air

Recently I changed the altenator and battery in my 97 Lumina. During one of the two changes i must have done something to mess the air up. When i turn the air on to blow directly straight it actually goes to the vents by the window. So someone i changed the one setting from being in use. Does anyone have any idea on how i did this while changing the battery and altenator and how i can fix it. Thanks for the help.

Just a thought....Maybe you broke one of the vaccum lines that are near the battery while changing it..after a while these lines become very brittle and easy to break