Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hello my name is ***** ***** thank you for your question.
These type of questions are hard to answer and the direction it normally requires is not a pretty answer.
The first thing I would do is go through all the mode door actuators to make sure they are working. If they are, then what you are dealing with a is a mode door in the air box has become jammed to stuck. These doors have a foam seal that goes around each door to seal it when closed. Some times, not often, the foam comes off and jams the mode door and can cause this. If this is found to be the case, the whole dash needs to be removed. The AC system recovered and Heater core hoses removed and the whole air box would need to be removed and opened up to be repaired.
This is most likely the issue if it started out of the blue.
Do you have any more questions on this?