A washing machine’s water level sensor is a critical component that controls the amount of water that fills the wash tub. This sensor works along with the machine’s control board to determine when to stop filling with water once it reaches the set level. If the water level sensor is defective, the washer may overfill or underfill with water during cycles. Fortunately, fixing a faulty water level sensor in your washing machine is a straightforward DIY repair that can be done in under an hour.
Replacing the sensor is the most common solution, but first you need to properly diagnose and test the existing sensor to confirm it’s the root of the problem. This article provides a complete guide on how to troubleshoot and replace a defective water level sensor in any top load or front load washing machine. Follow these steps to accurately test and fix your washer’s water level control.
Signs of a Faulty Water Level Sensor
There are a few common symptoms that indicate your washing machine’s water level sensor needs to be replaced:
Washer Overfills
The most obvious sign of a bad water level sensor is when the washer overfills and floods out water. This happens when the sensor fails to shut off the fill valve once the tub reaches the intended water level. Water will continue flowing into the tub, eventually overflowing out the door and onto the floor.
Washer Underfills
On the flip side, an intermittent or broken sensor may not properly register when the tub has filled to the correct level. This causes the washer to shut off the fill valve too early, leading to an underfilled tub. Clothes may not get fully submerged, resulting in cleaning problems.
Long Fill Times
It may take much longer than normal for the tub to fill if the sensor is covered in debris or slowly failing. The washer will sense the water level incorrectly, leading it to run the fill cycle longer before the proper level is reached.
Won’t Stop Filling
In severe cases, a completely broken level sensor won’t stop the fill valve at all. The tub will continue endlessly filling and overflowing unless power is cut to the washer or water supply shut off.
Fill Error Codes
Many washers will show an error code on the display when there’s an issue sensing the water level correctly. Common codes include F02, F08, LF, or any code indicating a fill or water level error. Refer to your washer’s manual for specific error code meanings.
Diagnosing the Water Level Sensor
Before replacing the water level sensor, it’s important to diagnose it to confirm that’s the true cause of the filling problems. Here are steps to properly test the existing sensor in your washer:
Visual Inspection
- Unplug the washer for safety.
- Access the sensor on the outside of the wash tub. It will be mounted near the bottom of the tub.
- Remove any debris or lint blocking the sensor.
- Check for corrosion on the sensor contacts or wire connections. Clean with rubbing alcohol if corrosion is present.
- Verify the sensor wire is still intact and securely plugged into the control board.
- Look for obvious physical damage like cracks or broken mounting tabs.
Resistance Test
Use a multimeter to check the sensor’s resistance:
- Set multimeter to OHMs setting.
- With sensor removed from tub, place probe tips on sensor contacts.
- Resistance should be around 10-50 OHMs when contacts are submerged in water.
- If no reading or vastly different reading, the sensor is likely faulty.
Voltage Test
You can also use a multimeter to check if the sensor is receiving power:
- Keep sensor plugged into washer’s control board.
- Set multimeter to Volts DC setting.
- Place probe tips on sensor contacts while machine fills.
- There should be 3-5 VDC during fill.
- Lack of power points to control board issues.
If tests confirm the sensor is defective, replacement is required.
How to Replace Water Level Sensor
Follow these steps to safely install a new OEM water level sensor:
Unplug Washer
Disconnect power to avoid electric shock while working on washer.
Access Sensor
The access steps vary by washer model:
Top load – Remove top panel, reach down into basin and remove sensor from outer tub wall.
Front load – Remove top and front panels. Sensor mounts on bottom exterior of outer tub.
Consult manual for model-specific instructions.
Remove Old Sensor
Once accessible, remove the bad sensor:
- Release wire from control board connection.
- Remove mounting screws or release tabs securing sensor.
- Clean any residual gunk from sensor mounting area on tub.
Install New Sensor
- Attach new sensor using original screws or tabs.
- Plug sensor wire into control board port.
- Ensure wire is routed properly to avoid pinching during reassembly.
Reassemble Washer
Replace all panels and parts in reverse order of disassembly.
Test Operation
- Reconnect power and water supply to washer.
- Run a test cycle and verify tub fills properly without overfilling or underfilling.
- Check that new sensor eliminates any error codes.
The new water level sensor should have your washer filling accurately again. Call a technician if any problems persist. Properly installed sensors rarely fail prematurely.
Troubleshooting Fill Problems
While a faulty water level sensor is the most likely culprit for fill issues, here are some other possible causes to check:
Control Board – Bad control board circuits or connections can prevent proper voltage from reaching sensor. Test voltage at sensor plug when tub is filling. No power indicates control board issues.
Pressure Switch – This switch cuts power to fill valve once proper air/water pressure is reached in tub. Faulty switch allows overfilling despite sensor working properly. Check pressure switch continuity and operation.
Water Inlet Valve – Debris or defects in the electromechanical fill valve can prevent it from closing completely, even when sensor stops the signal. Inspect valve filter screen and coil function.
Getting the exact root cause identified through testing avoids wasting time and money replacing non-faulty parts.
Preventing Water Level Sensor Failure
You can minimize future sensor issues by:
- Cleaning the tub and sensors regularly to prevent debris buildup.
- Leaving lid open after cycles to allow drying and prevent mold.
- Using front load washers only with HE detergent to reduce suds buildup.
- Avoid overloading the tub, which puts more water pressure on components.
- Shutting off water to washer when not in use to prevent leaks.
- Replacing fill hoses every 5 years to avoid bursting.
Water Level Sensor FAQs
How much does it cost to replace a water level sensor?
Replacement sensors cost $15-60 depending on brand. Samsung sensors are around $25. Whirlpool run $15-20. GE sensors cost approximately $60.
Where is the water level sensor located?
In top load washers, the sensor mounts on the external wall of the outer tub near the bottom. On front loaders, it’s externally at the bottom of the outer tub.
What causes a water level sensor to fail?
Excess dirt, debris, detergent buildup, and moisture corrosion are the most common causes of failure. Heavy water pressure and overfilling the tub can also damage sensors over time.
Does the water level sensor control the valve?
No, the sensor only detects water level and sends a signal to the control board. The board then controls power to the fill valve based on sensor input.
How do you bypass a water level sensor?
It’s not recommended to bypass the sensor, as this can lead to overflowing. The proper fix is to replace the faulty sensor. Temporarily you can halt filling by shutting off power or closing the water valves manually.
Can I just clean my water level sensor?
You can attempt cleaning debris from the sensor contacts and wire connections. But internal circuitry and sensing elements are likely still faulty. Replacement is the permanent solution.
Conclusion
Fixing a malfunctioning water level sensor is crucial to prevent flooding, underfilling, and other serious washing machine failures. Following the troubleshooting and replacement steps outlined in this article will get your washer safely filling properly again. With the right diagnosis and repair, you can stop wasting water and detergent on faulty fill cycles. And tackle this common washer repair yourself without the expense of a service call.