Nissan Repair: Air Flow Control not working correctly, air flow control, climate control units

Question
Hi,
I have a 2005 Nissan Sentra 2.4 GL.  My air flow direction control doesn't seem to be working anymore.  It doesn't matter if I set it to come out of the defrost, heater, or vents, it just blows out of all of them all the time, even when the air flow is set to 0 (off).  Any ideas on what could be wrong?

Answer
On automatic climate control units, vacuum lines are used to control the heater/ac air flow. The possibilities here, are a vacuum line may have been disconnected or a faulty control panel. If the blower motor keeps running after the switch is turned to off position, it is because it fails to cut off the power to the motor. A bad switch. On manual climate controls, linkages are used to switch the air flow dampers and one of them could have become inoperative. If you are not familiar with troubleshooting the heater, a/c system yourself, please take the car to a technician.