A/C Pressure Switch

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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 930 kPa (9.5 kgf/cm² , 135 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 Operation

A/C PRESSURE SWITCH OPERATION CHART

A/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 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 compressor clutch cycles. The radiator and A/C condenser fans operate at low speed.
High operating pressure: Above 1, 520 kPa (15.5 kgf/cm² , 221 psi) Below 2, 550 kPa (26.0 kgf/cm² , 370 psi)	CLOSED	CLOSED	The compressor clutch cycles. The radiator and A/C condenser fans operate at high speed.
Abnormally high pressure: More than 3, 140 kPa (32 kgf/cm² , 455 psi)	OPEN	CLOSED	The PCM disengages the 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.

Fig 1: Identifying High-Low Pressure Switch And Middle Pressure Switch

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Climate Control Door Positions

Fig 2: Climate Control Door Positions Air Flow Diagram (1 Of 2)

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 3: Climate Control Door Positions Air Flow Diagram (2 Of 2)

Courtesy of AMERICAN HONDA MOTOR CO., INC.