I drive a 2002 Saab 9-5. The air conditioning flow has stopped coming out of the vents on the dashboard which face the passengers and instead comes out of the defroster vents and the back seat vents. Any ideas?
The flap that directs airflow is malfunctioning, or rather the mechanism that moves the flap is. Defrost and floor seems to be the default position when these things fail.
Not sure if this is vacuum operated or electric on this car.
The vent doors operate using either vacuum air from the engine or are electrically operated as Mcparadise stated. I suspect your car uses the vacuum air since the trouble you are having is pretty common with that design.
There will most likely be a black air hose running from the engine area to under the dash on the passenger side. Make sure that hose has a vacuum on it while the engine is running. There also should be a vacuum reservoir under the hood for the system. Sometimes the connection to it gets broken and causes the trouble.