System Description

Climate Control

System Description




The air conditioning system removes heat from the passenger compartment by circulating refrigerant through the system.

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 (SANDEN SP-10) designed for the R-134a A/C compressor. Intermixing the recommended (PAG) refrigerant oil with any other refrigerant oil will result in A/C compressor failure.
- All A/C system parts (A/C compressor, discharge line, suction line, evaporator, A/C 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 SAEJ2210 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 A/C condenser), or too low (due to leakage), the A/C pressure switch stops the A/C request and the signal to the ECM and the A/C compressor stops operating.




- Middle pressure switch
If the refrigerant pressure goes above 1,470 kPa (15.0 kgf/sq.cm, 213 psi), the A/C pressure switch closes to signal the ECM to change the speed of the A/C condenser fan and radiator fan (high). When the pressure drops to 1,080 kPa (11.0 kgf/sq.cm, 156 psi) the switch opens and funs return to low speed.

Climate Control Unit Inputs And Outputs Part 1:

Climate Control Unit Inputs And Outputs Part 2:

Climate Control Unit Inputs And Outputs