Sounds like you may have a vacuum leak. The air vents are operated by vacuum on a very large number of vehicles.
Look under your dash for any hoses that may be disconnected, They are usually small in diameter. With the E-brake on and the car in park(neutral for stick shifts, and make sure you chalk the wheels) start the car and lay down on the floor and listen for a sound that be a light whistle, of the sound of sucking air. have a buddy or your wife/girlfriend lightly rev the engine while you are listening for those sounds under the dash. If you hear anything, then there is your answer.
If I understood your question correctly it should give you a good starting point, feel free to contact me!
Good Luck!
Look under your dash for any hoses that may be disconnected, They are usually small in diameter. With the E-brake on and the car in park(neutral for stick shifts, and make sure you chalk the wheels) start the car and lay down on the floor and listen for a sound that be a light whistle, of the sound of sucking air. have a buddy or your wife/girlfriend lightly rev the engine while you are listening for those sounds under the dash. If you hear anything, then there is your answer.
If I understood your question correctly it should give you a good starting point, feel free to contact me!
Good Luck!
