Low Pressure Sensor / Switch: Testing and Inspection
LPCO SWITCH TEST1. Remove protective rubber boot from low pressure cut-out switch and jump leads together.
2. Press the A/C button.
3. Start the engine.
4. If the cluch does not engage, the cycling clutch switch, wiring or fuse may be defective. Check the clutch circuit and clutch.
5. If clutch engages, connect the manifold gauge set and read evaporator suction pressure. At any pressure of 125kPag (18 psig) and above, switch must actuate clutch. If the evaporator suction pressure is below 172kPag (25 psig), refrigerant system is low on charge or empty due to a leak.
6. Connect boot on switch and perform step number 3. If the clutch does not engage, replace the switch.