How to Test a Washing Machine Water Level Switch

The water level switch is a key component in washing machines that controls the water fill level. It’s a fairly simple part but critical for proper machine operation. When this switch goes bad, the washer may not fill correctly or stop filling entirely. Testing the water level switch is easy to do yourself, saving the cost of a service call. With some basic tools and safety precautions, you can determine if this switch needs to be replaced.

Understanding How a Washing Machine Water Level Switch Works

The water level switch, also called a pressure switch, is a diaphragm-operated electrical switch mounted at the bottom of the washer’s outer tub. It has one or two rubber diaphragms inside that sense water pressure.

As the tub fills, pressure pushes against the diaphragm, which flexes and actuates a small electrical switch connected to it. This switch sends power to the water inlet valves, shutting off the water when the tub reaches the programmed fill level. If the pressure switch malfunctions, the washer may overfill, underfill, or not fill at all.

Common Water Level Switch Issues

  • Underfilling – If scale or debris builds up on the diaphragm, it may not flex properly, causing the tub to underfill with water. This prevents adequate washing and rinsing.
  • Overfilling – A stretched or torn diaphragm may not stop water flow when the tub is full, leading to overflowing.
  • No fill at all – A bad electrical switch or wiring failure can prevent power from reaching the water valves during the fill cycle.
  • Leaking – A damaged diaphragm can allow water to leak through the switch housing, which may appear near the base of the washer.

How to Access the Water Level Switch

The water level switch is located inside the washer cabinet, mounted to the outer tub. To access it, you must remove the washer’s front control panel or top cover. The steps to do this vary by model, but generally involve:

  1. Unplugging the washing machine from its electrical supply.
  2. Removing mounting screws from the top cover or front panel. These are often found inside the door rim or under pull-off trim caps.
  3. Detaching the top or front panel and propping it open. Be careful not to strain wiring harnesses.
  4. Locating the pressure switch. It will be mounted to the outer tub casing, often near the bottom center area.

Testing Procedures

Once you locate the water level switch, use these methods to test its operation:

Visual Inspection

  1. Check for any leaking from the pressure switch housing. Leaks indicate a damaged internal diaphragm.
  2. Make sure all wiring is intact with no loose, disconnected, or burned wires.
  3. Verify the switch is securely mounted to the tub with no loose or stripped mounting screws.
  4. Remove any debris, lint, or moisture from around the switch housing.

If leakage or damage is found, replacement is needed. Otherwise, continue to test switch operation.

Manual Test

  1. Disconnect power to the washer. Verify it’s unplugged.
  2. Locate the switch’s rubber diaphragm. Apply light finger pressure to deflect it inward, simulating water pressure in the tub.
  3. Have a helper observe the switch terminals inside the housing. The electrical contacts should open and close as the diaphragm moves.
  4. Release the diaphragm. The contacts should reset to their original position.
  5. Repeat this motion a few times. The switch action should snap on and off consistently.

Erratic operation or failure to activate indicates a bad switch needing replacement.

Fill Cycle Test

  1. Reconnect washer power and add a few wet towels to the empty tub.
  2. Set the washer to a low water level cycle like “small load” and start it.
  3. Watch to see if the tub fills to the proper level, then stops. The switch should close the water valves once the preset level is reached.
  4. If the tub overfills, underfills, or doesn’t fill at all, the switch is likely faulty. Further inspection or replacement is needed.
  5. To prevent a mess, immediately cancel the cycle and drain the tub if problems occur.

How to Replace a Bad Water Level Switch

If testing proves the switch is defective, replacement is necessary. Here are the steps:

  1. Unplug the washer and turn off the water supply lines.
  2. Disconnect the switch’s wiring harness and mounting screws. Caution – water may spill from the switch housing.
  3. Remove the bad switch. Note the exact mounting location and alignment.
  4. Install the new OEM replacement switch in the same orientation. Do not overtighten mounting screws.
  5. Attach the wiring harness to the identical terminals. Improper wiring can damage the switch or machine controls.
  6. Restore power and water supply. Check for leaks during operation. The new switch should function properly.

Replacement switches cost $15-50 and are widely available from appliance parts suppliers online and in-store. Only use a genuine OEM part to ensure compatibility and performance. Avoid cheap generic switches that may fail prematurely.

Safety Precautions

  • Disconnect electrical power to avoid shock hazard while testing or replacing the switch.
  • Wear eye protection in case debris or water sprays when accessing the switch.
  • Divert water supply lines during replacement to avoid flooding if leaks occur.
  • Confirm proper wiring connections to prevent electrical shorts or damage.
  • Leaking water around an old pressure switch may create mold. Wear a mask and clean with bleach.

Carefully following test procedures and power/water safety measures allows safe DIY diagnosis and replacement of a bad washing machine water level switch. Proper switch operation restores optimal fill levels for clean laundry.

Frequently Asked Questions About Washing Machine Water Level Switches

Testing and replacing the water level switch in your washing machine is usually a straightforward DIY repair. Here are answers to some commonly asked questions about dealing with water level switch issues.

Why does my washer keep overflowing?

If your washing machine keeps overfilling and overflowing with water, the water level switch is likely defective. A stretched or torn diaphragm may not properly stop the water valves when the tub is full. This leads to continual overflow.

How can I tell if my water level switch is bad?

Symptoms that indicate a faulty water level switch include:

  • Tub overfilling or underfilling
  • Washer not filling at all
  • Water leaking from the switch housing
  • Erratic electrical switch operation when manually tested

These issues signify it’s time to replace the faulty pressure switch.

Where is the water level switch on a washing machine?

The water level switch is mounted to the outer tub casing, usually low on the washer’s front side or bottom panel. To access it, remove the top cover or front control panel. Always unplug power first for safety when opening the cabinet.

Can I just clean my water level switch?

In some cases, debris or limescale on the rubber diaphragm can inhibit proper operation. You may be able to remove buildup to restore function. But a stretched or torn diaphragm causing overflow requires full replacement.

Do all washers have a water level switch?

Nearly all modern top and front loading automatic washers use a water level switch to control filling. Very old units used mechanical float valves instead, but pressure switches are now standard. Some HE top loaders monitor fill with electronic sensors.

How much does it cost to replace a water level switch?

Replacement water level switches typically cost $15-50. With DIY installation, you can save significantly compared to a $125-200 service call. Only use a new OEM factory switch to guarantee compatibility.

What if replacing the switch doesn’t fix the problem?

If overfilling or other issues continue after installing a new pressure switch, problems may lie with the water inlet valves themselves or the washer’s control module. Further diagnosis of these components may be needed.

Carefully testing washing machine water level switches and replacing faulty ones restores proper fill control for clean laundry results. With some DIY troubleshooting, most homeowners can fix switch issues and avoid costly repairs.

Step-by-Step Guide to Testing a Washing Machine Water Level Switch

Testing a malfunctioning washing machine water level switch is the first step in diagnosing and fixing fill problems. Follow these steps carefully:

Unplug the Washing Machine

Shut off power to avoid electric shock while testing the switch. Unplug the washer or disconnect the breaker supplying it.

Open the Washer Cabinet

The switch mounts inside the cabinet. Remove the top cover or front panel to access it. This requires taking out screws (usually on the inside rim or under trim caps).

Locate the Pressure Switch

It’s mounted to the outer tub, often low on the front or bottom. The switch has a plastic housing with wiring harness and rubber diaphragm.

Check for Visual Damage

Inspect for leaking, loose or disconnected wires, damaged mounting, etc. Leaks or damage mean replacement is needed.

Manually Actuate the Switch

With power still off, press the rubber diaphragm. Watch the switch terminals inside the housing. The contacts should open and close with each press.

Conduct a Fill Test

Reconnect power and run a low water level cycle. The tub should fill to proper level then the switch should shut the water off. Failure means the switch needs replacing.

Replace Faulty Switches

If tests reveal malfunction, install a new OEM factory replacement switch. Copy the wiring and orientation exactly. Verify it fills correctly.

Following proper electrical safety and visually inspecting, manually actuating, and performance testing the washing machine water level switch will accurately reveal if replacement is required. Take your time and be thorough when testing.

Choosing the Best Replacement Water Level Switch

Selecting the proper replacement water level switch ensures continued safe operation and optimal performance when the original switch has failed in your washing machine. Here are tips for choosing:

Purchase an OEM Factory Part

Opt for a genuine original equipment manufacturer (OEM) switch from the washer maker. Third party “compatible” switches often malfunction quicker.

Match the Part Number

The part number is usually printed on the old switch’s label. Match it precisely to guarantee the same fit, wiring, and performance.

Confirm Electrical Specs

Voltage, amperage, and connection type should match the original. This data should be available on the switch specifications.

Evaluate Switch Type

Most are single diaphragm, but some older or commercial units use dual diaphragm types. Install the same variety.

Check Pressure Settings

Replacement switch actuation pressure must equal OEM specs, often 2-6 psi. Incorrect settings cause inaccurate fill levels.

Include mounting Hardware

Ensure any special brackets or fasteners needed to mount the new switch are included for proper installation.

Buy from Reputable Sellers

Purchase switches sold by appliance parts warehouses or the OEM manufacturer to avoid counterfeit or defective parts.

Choosing the right replacement water level switch using the OEM part number while verifying pressure, electrical, and mounting requirements will restore your washer’s fill system to optimal functionality.

How to Prevent Washing Machine Water Level Switch Problems

While water level switches inevitably fail over time, there are steps you can take to maximize the life of this key washer component and avoid premature issues:

Use Water Softener if Needed

Hard water mineral deposits on the switch diaphragm can inhibit proper flexing and operation over time. Using a water softener prevents scale buildup.

Don’t Overload the Tub

Overstuffing the washer drum strains the outer tub, which transfers extra stress and pressure onto the switch mount. Only wash recommended loads.

Clean Gasket and Drain Regularly

Debris, lint, and soap scum can clog the drain, causing excess water to back up and strain the diaphragm. Keep drain pathways clear.

Avoid Low Water Levels

Filling at minimum levels strains the tub and switch as there is less cushioning water to distribute mechanical shocks during agitation. Use higher levels when possible.

Don’t Over-Tighten Water Connections

High water supply pressure stresses the diaphragm and can lead to premature failure. Don’t overtighten supply hoses. Use pressure regulators if needed.

Check Overflow Periodically

Run a tub-full level cycle and verify proper fill shutoff and no overflow. This ensures the switch is operating as designed.

With proper care and maintenance, a washing machine’s water level switch can reliably control washer fill levels for years. But at the first sign of inaccurate fill issues, test and replace the switch.

Troubleshooting Common Washing Machine Water Level Switch Problems

Water level switch issues can sometimes be fixed without replacement. Try these troubleshooting steps for common problems:

Overflowing Washer

  • Clean scale off diaphragm with vinegar.
  • Check that drain line is clear of debris clogging outflow.
  • Verify fill hoses are not overtightened causing excess inlet pressure.
  • Replace switch if cleaning and adjustments don’t stop overflow.

Underfilling Tub

  • Check for kinked or blocked supply hoses limiting water flow.
  • Remove any debris blocking the pressure switch housing.
  • Test and replace the switch if it fails to actuate properly during manual test.

Leaking Switch

  • Tighten mounting screws to stop minor housing leaks.
  • Clamp or replace leaky inlet hoses spraying water on switch.
  • Full switch replacement is required if diaphragm seal is compromised.

No Fill At All

  • Ensure supply valves are open and water lines unobstructed.
  • Check for faulty wiring connections or broken wires.
  • Verify switch makes distinct “click” when diaphragm is pressed. If not, replace it.

With some basic troubleshooting, minor water level switch problems can potentially be corrected without replacement. But for most issues, installing a new OEM switch is the proper fix.

How to Prevent Expensive Washer Repairs

Washing machine repairs can be costly, ranging from $200 up to over $500 for complex control board or motor replacements. Luckily, many expensive washer repairs can be avoided by proper maintenance and catch issues early. Here are some tips:

Clean with Affresh Regularly

Run a cleaning cycle with Affresh or other washer cleaner monthly. This prevents soap scum, mold, and debris buildup that can lead to odor and mechanical problems.

Inspect Door Gasket

Check the rubber door seal for any cracks or damage that could allow water to leak out, potentially getting into control components. Replace worn seals.

Use High-Quality Detergent

Poor detergents can leave residue that blocks valves and causes leaks. Invest in a top detergent like Persil, Tide, or Gain to prevent buildup.

Don’t Overload the Drum

Jamming too many clothes into the tub strains the suspension system, motor, and other mechanics. Only wash recommended load sizes.

Level the Machine Properly

An unleveled washer vibrates excessively and can “walk”, potentially causing leaks or tripping breakers. Always level front loaders precisely.

Listen for Problems

Unusual noises like scraping, grinding or squealing indicate a mechanical problem. Diagnose and fix minor issues before catastrophe.

With vigilant preventative maintenance and listening for trouble signs, costly washer repairs can be avoided. But of course, components like the water level switch will still wear out over time. Test and replace these parts as needed.


The washing machine’s water level switch is a small but critical part that controls proper fill levels for effective cleaning. When this pressure sensor switch malfunctions, underfilling, overflowing and other problems result. Diagnosing issues with visual inspection and manual switch actuation allows identifying faulty switches needing replacement.

Installing a new OEM factory water level switch matched to your model’s specifications, along with safely accessing the switch housing and properly reconnecting wiring, will successfully restore accurate fill control. Combined with preventative washer maintenance and repair, testing and replacing bad water level switches as needed will extend the life and functionality of your valuable washing machine.

Meta Description

Diagnose washing machine water level switch problems causing improper fill levels. Steps to safely access, test, and replace the pressure sensor switch when it fails.