Operation CHARM: Car repair manuals for everyone.

System Description




System Description
The air conditioning 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 (DENSONO-OILS) designed for the R-134a compressor.
- 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) are designed for refrigerant R-134a. Do not exchange 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.

A/C Pressure Switch
The A/C pressure switch consists of a high-low pressure switch (A/C pressure switch A) and a middle pressure switch (A/C pressure switch B).




- High-Low pressure switch
If the refrigerant pressure becomes too high (due to blockage or lack of airflow at the condenser), or too low (due to leakage), the A/C pressure switch stops the A/C request a signal to the PCM and the compressor stops operating.










- Middle pressure switch
If the refrigerant pressure goes above or below 1,520 kPa (15.5 kgf/sq.cm, 220 psi), the A/C pressure switch opens or closes to signal the PCM to change the speed of the condenser fan and radiator fan (high-low).

Climate Control Unit Inputs And Outputs:




Climate Control Unit Inputs and Outputs