Heating and Air Conditioning: Description and Operation

The air conditioner system removes heat from the passenger compartment by circulating refrigerant through the system as shown.

This vehicle uses HFC-134a (R-134a) refrigerant which does not contain chlorofluorocarbons. Pay attention to the following service items:
- Do not mix refrigerants CFC-12 (R-12) and HFC-134a (R-134a). They are not compatible.
- Use only the recommended polyalkyleneglycol (PAG) refrigerant oil designed for the R-134a compressor (SANDEN: SP-10). Intermixing the recommended (PAG) refrigerant oil with any other refrigerant oil will result in compressor failure.
- All A/C system parts (compressor, discharge line, suction line, evaporator, condenser, receiver/dryer, expansion valve, O-rings for joints) have to be proper for refrigerant R-134a. Do not confuse with R-12 parts.
- Use a halogen gas leak detector designed for refrigerant R-134a.
- R-12 and R-134a refrigerant servicing equipment are not interchangeable. Use only a recovery/recycling/charging station that is U.L.-listed and is certified to meet the requirements of SAE J2210 to service R-134a air conditioning system.
- Always recover the refrigerant R-134a with an approved recovery/recycling/charging station before disconnecting any A/C fitting.


The heater control panel receives battery voltage at all times through fuse 47. With the ignition switch in ON (II), voltage is supplied to the heater control panel through fuse 17. The control panel is grounded at G402.

The heater control panel controls the air delivery motors, and supplies a 5 VDC reference voltage to the air mixture control motor.

The air mixture and mode control motors each receive inputs from the heater control panel. The air mix motor regulates the mixture of cold and hot air by varying the position of the heater-evaporator door.

The mode control motor controls the direction and volume of outlet air. The air flow can be directed to the dashboard vents or the corner vents.
Both the air mixture control motor and mode control motor are grounded by the heater control panel.

The recirculation control motor receives battery voltage through fuse 17 when the ignition switch is in ON (II). It regulates the position of the fresh/recirc door, and is controlled by two position inputs from the heater control panel ("Recirc" and "Fresh").