Fig. 161: Rear Heater AC Housing Description

Models with the rear heating-A/C system use a rear heater-A/C housing (1) that combines A/C and heating capabilities into a single unit mounted within the rear passenger compartment. The rear heating-A/C system is a blend-air type system. A blend-air door controls the amount of conditioned air that is allowed to flow through, or around, the heater core (9). The rear A/C system is designed for the use of a non-CFC, R-134a refrigerant and uses an A/C expansion valve (7) and A/C evaporator (6) to cool and dehumidify the incoming air prior to blending it with the heated air. A temperature control determines the discharge air temperature by operating the blend door actuator (3), which moves the blend-air door. This allows an almost immediate control of the output air temperature of the rear system. The mode control operates the mode door actuator (2) that positions the mode-air door to direct the flow of the conditioned air out the upper or lower air outlets, depending on the position selected. Both electric door actuators are connected to the vehicle electrical system by the rear heater- A/C wire harness (8). The rear blower motor (4) controls the velocity of air flowing through the rear heater-A/C housing by spinning the blower wheel within the rear housing at the selected speed by use of the rear blower motor resistor or power module (5) (depending on manual or automatic control).

The rear heater-A/C housing must be removed from the vehicle for service of the mode door actuator and blend door actuator and it must be disassembled for service of the A/C evaporator and the heater core.