Nissan Repair/'06, nessan, sentra, ventilation
the dial that switches the direction of the air, from windshield to floor and so on, is not working. it is only working
straight ahead, like for A/C. Knob turns but direction does not change.
Hi Alex -
This is controlled by vacuum lines. Check in the engine compartment and ensure that all vacuum hoses are not broken or disconnected.
It is also possible that the door that switched the direction of the air in the AC duct is stuck. To check this, the ductwork under the dashboard has to be removed to expose this inner door. Then you can see if it is operating properly.
Hope this helps -