To test a washing machine pressure switch, first disconnect power and remove the switch and air pressure tube. Examine the tube for blockages or cracks, then use a multimeter to check electrical continuity while applying air pressure. Changes in continuity confirm the switch is working correctly.
The pressure switch tells your washer how much water to let in before beginning the wash or rinse cycles. If it fails, the washer can overfill, underfill, or stop mid-cycle. Understanding how it functions, and testing it safely, ensures accurate water levels and reliable cleaning.
How does a washing machine pressure switch work?
A washing machine pressure switch uses air pressure to control how much water enters the tub. As the water level rises, air pressure builds in a small hose connected to the switch, triggering it to stop water flow once the correct level is reached.
The pressure switch is the part that tells your washer when the tub is full enough for a wash cycle. Once the control or timer starts the cycle, voltage is sent to the water inlet valve to fill the tub. The pressure tube connected to the side or bottom of the tub traps air that compresses as the water level rises. When enough pressure builds, roughly 8-18 gallons for top-load washers or 2-5 gallons for front-load washers, the switch shuts off voltage to the valve, stopping the water.
During the rinse cycle, the process repeats. After the washer drains, the pressure in the tube drops, signaling the switch to reopen the inlet valve for fresh rinse water. Once full again, the switch cuts voltage to the valve, allowing power to redirect to the drive motor or rotor/stator assembly to begin agitation and spinning. This pressure-based design ensures every cycle fills just enough water.
How can a washing machine pressure switch malfunction?
A pressure switch can fail mechanically or electrically. If it’s stuck closed or the air pressure tube has a hole, the washer might overfill. If it’s blocked or has no continuity, the washer might not fill or start at all.
Because both the switch and its tube work together, damage to either can throw the entire water-level system off balance. A cracked or loose air hose prevents the switch from detecting pressure accurately, while a clogged one may trap air and stop the washer from refilling after draining.
An intermittently failing pressure switch might misread the water level, leaving a wash cycle unfinished or repeating endlessly. If your washer overflows, doesn’t fill, or pauses mid-cycle, the pressure switch is one of the first components to inspect.
How do I test a washer pressure switch?
You can test a washer pressure switch in four steps: remove the switch and air tube, check the tube for blockages, identify the switch terminals, and use a multimeter to confirm changes in continuity when air pressure is applied.
- Remove the pressure switch and air pressure tube – unplug the washer or shut off power. On front-load models, the pressure switch sits under the top panel, often on the frame. On top-load models, it’s typically behind the control panel or rear panel. Disconnect the wires, twist or unclip the switch, and detach the air tube from the tub port.
- Examine the air pressure tube – before testing electrically, inspect the tube for obstructions, cracks, or holes. If it’s damaged, replacing it with a new air pressure tube often solves the issue. Make sure the replacement fits snugly on the pressure switch port to seal air pressure properly.
- Identify the pressure switch’s terminals – most switches have three terminals: common, normally closed, and normally open. The normally closed terminal supplies power to the inlet valve, while the normally open one powers the drive motor. Use your washer’s wiring diagram to identify each correctly before testing.
- Use a multimeter to test the pressure switch terminals – set your multimeter to the lowest ohms range. Touch the black lead to the common terminal and the red lead to the normally closed terminal – you should see near-zero resistance, indicating continuity. Blow gently into the air tube; you should hear a click and see continuity break.
Next, move the red lead to the normally open terminal. This circuit should show no continuity until you apply air pressure, which should then create continuity. If readings remain unchanged or incorrect throughout, the switch is defective and needs to be replaced with a compatible OEM part.
Where can I find washer repair resources and model-specific guides?
Repair Clinic provides model-specific videos, diagrams, and procedural guides to help you safely replace or test your washer’s pressure switch. Just enter your washer’s model number in the Repair Clinic “Videos & Articles” library to find the right tutorial.
You can also go directly to replacement instructions, such as:
- How to replace a pressure switch on an Electrolux front-load washer (Model EFLS627UTT).
- How to replace the air pressure tube on a Whirlpool top-load washer (Model WTW4815EW0).
Repair Clinic’s database also links directly to Whirlpool washer parts and hundreds of other OEM components ready to ship.
Why should I use genuine OEM parts instead of generic replacements?
Using genuine manufacturer parts ensures perfect fit and long-term reliability. Generic parts may look similar but often lack exact tolerances or material quality, which can lead to faster wear or inaccurate operation of key components like the pressure switch.
When replacing your pressure switch, air pressure tube, or any other washer component, always choose OEM parts. Genuine replacements are designed and tested for your washer’s brand and model, ensuring proper performance and safety.
Repair Clinic carries original manufacturer parts for major brands including Whirlpool, LG washer parts, Samsung, Maytag, GE, Kenmore, Bosch, and Frigidaire.
Enter your washer’s model number in the Repair Clinic “Search Parts Online & Get Answers” bar to generate a list of compatible parts. Then use the “Part Category” and “Part Title” filters to quickly find the exact washer pressure switch] or air pressure tube you need.
How can I prevent future washing machine pressure switch issues?
Keep the pressure switch working properly by maintaining clean air tubes and avoiding detergent overuse, which can lead to buildup inside the washer. Periodically inspect hoses for cracks or leaks and replace worn parts before they fail.
Also, never overload your washer, as excess weight and vibration can loosen electrical connectors or damage sensors. A quick monthly inspection, checking for moisture, corrosion, or dislodged tubing, prevents small issues from turning into expensive failures.
For more washer care advice, browse the Repair Clinic “Videos & Articles” library for cleaning and troubleshooting guides specific to your model.
Where can I buy the right parts to test or replace my washer pressure switch?
You can buy genuine pressure switches, air tubes, and other washer parts directly from Repair Clinic. Enter your model number on RepairClinic.com to view parts guaranteed to fit your appliance.
Each product page includes installation videos, schematics, and troubleshooting guides for top-load and front-load washers. Whether you’re replacing a pressure switch, air pressure tube, or related electrical component, Repair Clinic ships OEM parts fast with a 365-day return policy.
Shop genuine washer parts at Repair Clinic today and keep your washing machine running quietly, efficiently, and accurately.