System Valves and Switches

A/C REFRIGERANT SYSTEM (R-134A), VALVES/SWITCHES

Note
The following A/C system switches are available in different versions. Always consult the proper parts in formation to ensure correct switch application.





A/C REFRIGERANT HIGH PRESSURE SWITCH (F 23)

FUNCTION

Switches coolant fan (V 7) to second speed when A/C system pressure increases.




A/C REFRIGERANT HIGH PRESSURE SWITCH (F 118)

FUNCTION

Switches A/C clutch (N 25) OFF if system pressure is too high.


A/C REFRIGERANT LOW PRESSURE SWITCH (F 73)

FUNCTION




Switches A/C clutch (N 25) 0FF if system suction pressure is too low (low refrigerant charge). This switch protects the compressor if the refrigerant system is empty.


A/C SYSTEM SWITCHES, VALVE CONNECTION




A Schrader valve is installed under the A/C system switches so the switches can be replaced without discharging the A/C system.

- A/C system low and high pressure switches use different size threads.

- Use only the correct switches and 0-ring seals specified for use with R-134a refrigerant and PAG oil.

A - Switch connection (soldered)
B - 0-ring seal
C - Schrader valve insert





A/C COMPRESSOR SPEED SENSOR (G 111)

- inductive sensor (4 pulses per compressor rotation)

- determines A/C compressor speed; the A/C control head (Automatic climate control) compares compressor speed to engine speed and calculates belt slippage (as a percentage) and switches compressor OFF if slippage is too large (for example, if belt is too loose.)