Refrigerant Pressure Sensor / Switch: Description and Operation

A/C Refrigerant System Component Functions, Overview

A/C Pressure Switch -F129-







Switch has three functions:

- Switches the A/C clutch -N25- off when excessive refrigerant circuit pressure is present (e.g.: insufficient air flow over condenser or when overcharged).
- Switches the A/C clutch -N25- off when insufficient refrigerant circuit pressure is present (e.g.: when refrigerant has leaked out)
- Switches on the second speed coolant fan -V7- when refrigerant circuit pressure increases.

Function






Pressure switch component between blue wires switches A/C clutch -N25- off when too little or excess refrigerant system pressure is present.

- Switch opens (compressor off) below 2 bar (29.4 psi) and closes (compressor on) above 3 bar (43.5 psi).
- Switch opens (compressor off) above 32 bar (464 psi) and closes (compressor on) below 24 bar (348 psi).
- Switch closes (fan on) above 16 bar (232 psi) and opens again (fan off) below 12.5 bar (181.25 psi).