Nissan Repair: air conditioner, valve fitting, expansion valve

Question
last summer, my 2000 Altima was sitting at idle with the air conditioner running when all of a sudden, a mist-like substance began blowing out of the vents, almost like the car was overheating I thought.  After that, the air conditioner has ceased to work.  Any ideas what might have gone wrong and what it'll entail to fix it?  Thanks!

Answer
Sheli,

That fog was the refrigerant.  My thought is the evaporator core has developed a leak or the expansion valve fitting has blown.  In either case you will need to have the system checked and then, once verified take the airconditioner/heater box out from under the dash to access the evaporator assembly to replace it or the expansion valve before the system will work again.  Then, it will need to be evaporated and recharged.