Nissan Repair: Nissian Quest Air Conditioning Problem, nissan service manual, automatic climate control

Question
My 96 Nissan Quest air conditioning is blowing warm air in the front where the drive and passager seats.  The rear is blowing cool air.  I have don't have any clue what could cause this.  

Answer
Binh,

It sounds like a blend door is stuck up front.  Let me explain this problem.  There is a fiberglass/plastic composite box under the dash that contains a heater core and a evaporator.  The evaporator is what makes the air cool when the airconditioner is on.  Since you have dual air there is another path for airconditioning in the back.  If one works they both should.  So, it should not be the compressor or a leak.  The air is managed by doors that are controlled by the master switch you manage and it moves these doors under the dash.  I think the blend door is not working properly and it is either the motor that works the door or the control that could be defective.  This is especially true if you have automatic climate control.  First, I would look under the dash and see if the control arm moves when you turn the airconditioner on, with the engine running, and see the process.  It would really pay to get a Nissan service manual since it shows the diagrams of how the components operate.  You can get one of these electronically by going to the nissanusa.com page and paying $20 bucks for an hour of access to your particular vehicle.  The manual is in .pdf format so all you do is go to the climate control part of the manual and download that part.