Whirlpool Washer High-Pitched Hum During Wash Cycle:... | appliancefaults.com

Technical Background:

The MCU (Main Control Unit) regulates the motor speed and pump operation via relays and triacs. Voltage paths from the MCU control board supply power to the motor and drain pump. A fault in the MCU or a component in the voltage path can cause the motor or pump to receive incorrect voltage, resulting in a humming sound or improper operation.

Symptoms:

The homeowner observes a high-pitched humming sound emanating from the Whirlpool washing machine during the wash cycle. The washer may or may not be agitating or spinning properly.

Possible Causes:

Worn or failing motor bearings.
Partially blocked drain pump.
Foreign object lodged in the pump impeller.
Defective drive belt (if applicable to the model).
Issues with the main control board (MCU) causing incorrect motor speed control.
Partially seized clutch or transmission (direct drive models).

Solution:

1

Disconnect power to the washer at the breaker panel (LOTO).
2

Remove the front or rear access panel (depending on model) using a 1/4-inch nut driver.
3

Inspect the motor and pump for any visible obstructions or damage. Check the drain pump impeller spins freely by hand.
4

Visually inspect the drive belt (if present) for wear, cracks, or looseness.
5

Use a multimeter to test the motor windings for continuity. Expected resistance values vary by motor type. Consult the service manual.
6

Check the drain pump voltage during the wash cycle using a multimeter. Expect 120V AC if the pump is activated.
7

If the voltage to the pump is correct and the pump is still humming, replace the drain pump.

Safety Warning:

Disconnect power to the washing machine at the breaker panel before performing any repairs. High voltage is present inside the appliance, posing a risk of electric shock. Use proper lockout/tagout (LOTO) procedures.

Prevention:

Regularly inspect and clean the drain pump filter to prevent blockages. Avoid overloading the washer to reduce stress on the motor and drive components. Periodically check the drive belt (if applicable) for wear and replace as needed.

Expert Tip:

Many Whirlpool washers have a diagnostic mode. Consult the service manual to enter the diagnostic mode and retrieve any error codes that may be stored in the MCU. This can help pinpoint the source of the problem.

Frequently Asked Questions

•What resistance should I expect when testing the motor windings?

The expected resistance values vary depending on the motor type. Consult the service manual for your specific Whirlpool washer model. However, a general rule is that open windings (infinite resistance) or shorted windings (very low resistance) indicate a faulty motor.

•How do I access the diagnostic mode on my Whirlpool washer?

The procedure for accessing the diagnostic mode varies depending on the model. Typically, it involves pressing a specific sequence of buttons on the control panel within a short time frame. Refer to your washer's service manual for the exact instructions.

•What if the voltage to the drain pump is lower than 120V AC?

If the voltage to the drain pump is significantly lower than 120V AC (e.g., below 100V AC), it could indicate a problem with the MCU, wiring harness, or a faulty relay. Check the wiring harness for loose connections or damaged wires. If the wiring is good, suspect a faulty MCU and consider replacing it.

Whirlpool Washer High-Pitched Hum During Wash Cycle: Troubleshooting & Repair

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What resistance should I expect when testing the motor windings?

•How do I access the diagnostic mode on my Whirlpool washer?

•What if the voltage to the drain pump is lower than 120V AC?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: