Q: Where Is the A/C Low-Pressure Switch Typically Located?
A: The A/C low-pressure switch is usually on one of the air conditioning pipes that’s attached to each side of the A/C compressor. The low-pressure side is typically the one with the smaller pipe.
A/C high pressure switches are typically used to prevent compressor damage.
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Pro Tip: On cold days even if the refrigerant isn’t low, the compressor will cycle because when it comes to refrigerant, low ambient temperature means lower pressure.
The low pressure switch will be mounted on the accumulator or somewhere between the accumulator and the compressor on the suction line, where the refrigerant is a low pressure gas.
On the other hand, the high-pressure switch prevents excessive refrigerant pressure buildup that can damage the compressor. Sometimes the high pressure switch is built into the compressor (as on older platforms) but more often it’ll be on the discharge line between the compressor and the condenser where the refrigerant is a high pressure gas.
Tips on How to Access the A/C Low-Pressure Switch
On newer vehicles, using a scan tool while the air conditioning system is running is one of the fastest ways to diagnose problems with the A/C low-pressure switch. But if you don’t have a scan tool, you can still assess the pressure switch manually using an A/C pressure gauge set.
Also, still on newer vehicles, there will also typically be a transducer rather than a switch that will report actual refrigerant pressures to the ECM/PCM or the A/C amplifier.
If the low pressure switch sticks closed, the evaporator will become a block of ice and airflow will cease. If the pressure switch fails open, the compressor won’t engage even if the refrigerant level is as it should be.
If the low pressure switch sticks closed, the evaporator will become a block of ice and airflow will cease.
– Richard McCuistian, ASE Certified Master Automobile Technician
In closing, recognize that low pressure cutout switches are typically used only on fixed orifice systems, since the expansion valve on TXV systems does the same job the low pressure cutout switch does, except that it regulates refrigerant flow through the evaporator based on suction line temperature.
Some systems have an evaporator temperature switch or sensor for the same reason and will cycle the compressor.
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Morning, my 2013 ford ranger 3.2 xlt shows a fault code of P0532 aircon pressure sensor circuit low. I’m striggling to find the low pressure sensor. i don’t find anything on the low side pipe but do find the sensor for the high pressure sensor. it’s located on the pipe line. please assist finding it. if possible a photo of the location.