General Description

Both A/C systems are designed to provide a comfortable environment inside the passenger compartment, regardless of weather conditions outside of the vehicle. The systems do this by cooling, dehumidifying, heating and circulating the air that enters the passenger compartment.

Both systems consist of four different major parts:

^ Refrigeration system.
^ Heater system.
^ Air distribution system.
^ Mode/temperature control system.

Most aspects of the HVAC systems that are unique to these systems are discussed here, along with the mode/temperature control systems.
Vehicles equipped with the dual zone A/C systems may also be equipped with steering wheel controls that operate some A/C system and radio functions.

AUTOMATIC A/C SYSTEM (C68)

The automatic A/C system (C68) is a vacuum and electronically controlled heater, ventilation and air conditioning system. Both electronic and vacuum circuits determine air intake and discharge locations. The electronic circuits also control mode, A/C compressor clutch operation, fan operation and discharge air temperature.

The driver may select a desired interior temperature (the SET temperature), fan speed and mode of operation from the system control panel. One of these modes is a fully automatic mode in which the system determines the appropriate air intake and discharge locations, fan speed, and discharge air temperature, according to the driver selected temperature and information provided by the system's network of sensors.

The automatic A/C system utilizes a variable displacement orifice tube (VDOT) type refrigeration system. This refrigeration system is described in Heating, Ventilation, and Air Conditioning.