Refrigerant Pressure Sensor / Switch: Description and Operation

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 (15.5kgf/sq.cm, 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 d drops below 1,230 kPa (12.5 kgf/sq.cm, 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.