S15/T15 Sonoma P/U 2WD V6-4.3L VIN X (1998)
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Refrigerant Pressure Sensor / Switch: Description and Operation
Pressure Cycling Switch
A pressure cycling switch controls the refrigeration cycle (the ON and OFF operation of the compressor). The switch senses the low-side pressure as an
indicator of evaporator temperature. The switch protects the system from freezing. The switch senses refrigerant pressure on the suction side of the
system. This switch is mounted on a standard service fitting on the accumulator. This switch also provides compressor cutout during cold weather.
The low-side pressure cycling system also protects the compressor. Low-side pressures might not close the contacts of the pressure switch if a massive
discharge occurs in the low side of the system. Low-side pressure also might not close the contacts if the orifice tube clogs. Insufficient cooling and rapid
compressor clutch cycling are noticed at high outside temperatures in the event of a low charge.
You can replace the pressure cycling switch without removing the refrigerant charge. You must install a new O-ring seal when you replace the pressure
switch. The switch must be assembled to the specified torque of 4.5 N.m (40 lb in).