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 signal to the PCM and the A/C compressor stops operating.
- Middle pressure switch
If the refrigerant pressure goes above 1,520 kPa (15.5 kgf/cm2 , 221 psi), the A/C pressure switch closes to signal the PCM to change the speed of the A/C condenser fan and radiator fan to high. When the refrigerant pressure drops below 1,230 kPa (12.5 kgf/cm2 , 178 psi), the A/C pressure switch opens to signal the PCM to change the speed of the A/C condenser fan and radiator fan to low.
A/C PRESSURE SWITCH OPERATIONA/C System Pressure Hi-Low Pressure Switch Medium Pressure Switch System Operation Abnormally low pressure: - Below 196 kPa (2.0 kgf/cm2 , 28 psi)
OPEN OPEN The PCM disengages the A/C compressor clutch.Radiator and A/C condenser fan control is based on engine coolant temperature. Normal Operating pressure: - Above 225 kPa (2.3 kgf/cm2 ,33 psi)
- Below 930 kPa (9.5 kgf/cm2 ,213 psi)
CLOSED OPEN The A/C compressor clutch cycles. The radiator and A/C condenser fans operate at low speed. High Operating pressure: - Above 1520 kPa (15.5 kgf/cm2 ,221 psi
- Below 2550 kPa (26.0 kgf/cm2 ,370 psi
CLOSED CLOSED The A/C compressor clutch cycles. The radiator and A/C condenser fans operate at high speed. Abnormally High pressure: - More than 3140 kPa (32 kgf/cm2 , 455 psi
OPEN CLOSED The PCM disengages the A/C compressor clutch.Radiator and A/C condenser fan control is based on engine coolant temperature. NOTE: When the A/C system pressure is between the listed ranges, the pressure switches are in a transition state. The switch behavior depends upon whether the pressure is rising or falling.