Rear Air Conditioning

1 Vent
2 Fan
3 Evaporator
4 Fan control module
5 Refrigerant medium pipe
6 Solenoid Valve
7 Air intake

Certain cars of year model 1992 were equipped with rear air conditioning (SAAB 9000 CD with Automatic Climate Control (ACC)). This was to create a more even cooling of the cabin and in order to be able to reduce fan speed and maintain cooling.

An evaporator with fan is located in the luggage compartment and draws air via an air intake under the rear seat. The air is cooled and channeled to a vent in the parcel shelf. Coolant is lead to and from the rear evaporator in two insulated pipes under the car. A solenoid valve under the rear evaporator ensures that the oil returns to the compressor when the rear A/C unit is switched off. Otherwise, the oil may remain stationary in the pipes causing compressor breakdown. The solenoid valve also prevents circulation of refrigerant.

Other parts in the system are common to cars without rear A/C but the quantity of oil and quantity of refrigerant has been increased.
Note that it is not advisable to direct the center front vent diagonally upwards when rear A/C is used. If this is done, the air streams meet at the roof and cause cold air to drop on to the necks of the driver and passenger.