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How To Test A/C High Pressure Switch

If you have an air conditioning unit and are experiencing issues with it, chances are your high pressure switch is to blame. This is a common issue because these switches are often neglected and left unprotected. In this blog post, we will show you how to test a high pressure switch and resolve any problems that may be causing your unit to malfunction.

What is a A/C High Pressure Switch?

A/C high pressure switch is a safety device that opens the compressor’s intake valve when the A/C system’s pressure reaches a certain level. The switch is usually in the engine compartment.

How to Test a A/C High Pressure Switch

If your A/C is not blowing cold air, there is a good chance that the high pressure switch may be defective. To test the high pressure switch, first determine whether or not you are using a split system. If you are not using a split system, then proceed to step two. If you are using a split system, disconnect both HVAC lines going into the house from the high pressure switch and use a voltmeter to measure voltage at each terminal. The voltage should be approximately 12 volts. If it is not, then the high pressure switch may be defective and need to be replaced.

What to do if the A/C High Pressure Switch is Malfunctioning

If you are having trouble with your air conditioning, one possible cause is a malfunctioning high pressure switch. To test the switch, follow these steps: Disconnect the power to the unit. Open the cover of the high pressure unit and remove the cap on top of the motor. Turn on the power to the unit and watch for the fan to start spinning. If it does not start spinning after a few seconds, replace the high pressure switch.


If you’re experiencing high pressure in your air conditioning unit, it’s likely that the switch is malfunctioning. In this article, we’ll show you how to test a/c high pressure switch and identify the problem if it exists. We hope this information will help you get your AC unit up and running again as quickly as possible!