Whirlpool WRX735SDHZ Refrigerator: Loud Screeching Noise... | appliancefaults.com

Technical Background:

The MCU (Main Control Unit) controls the defrost cycle and icemaker operation, activating various components like the defrost heater and fan motors. Voltage is supplied to the fan motors during these cycles. The thermistors monitor the temperature and signal the MCU accordingly.

Symptoms:

US homeowner reports a loud screeching noise emanating from the Whirlpool WRX735SDHZ refrigerator specifically during the spin cycle (defrost or icemaker fill).

Possible Causes:

Icemaker fan motor bearing failure
Evaporator fan motor obstruction or bearing failure
Defrost cycle component interference
Ice buildup rubbing against the fan blade
Condenser fan blade interference

Solution:

1

Unplug the refrigerator or turn off the breaker to the refrigerator circuit at the breaker panel.
2

Locate the evaporator fan motor, typically behind an access panel in the freezer compartment. Use a 1/4-inch nut driver to remove the panel screws.
3

Inspect the fan blade for ice buildup or obstructions. Remove any ice carefully with a plastic scraper. Check for free rotation of the fan blade.
4

Access the icemaker fan motor and repeat the ice buildup and free rotation check. Listen to both motors while manually spinning them to hear if either motor is making the screeching noise.
5

If the fan motor is suspected, use a multimeter to test the motor windings for continuity. A reading of OL (open line) indicates a faulty motor. Disconnect the motor and test the voltage going to it during a defrost or icemaking spin cycle - it should read 120V AC.
6

If the motor is faulty, replace it with a new OEM Whirlpool fan motor.
7

Reassemble the refrigerator and plug it back in or turn the breaker back on.

Safety Warning:

Always disconnect power to the refrigerator before performing any repairs. Use Lock-Out/Tag-Out (LOTO) procedures to ensure the circuit remains de-energized. High voltage is present in the control circuits.

Prevention:

Periodically inspect the freezer compartment for excessive ice buildup. Ensure the refrigerator doors are sealing properly to prevent moisture ingress.

Expert Tip:

To force a defrost cycle, simultaneously press and hold the 'Freezer Temp' and 'Ice Type' buttons for approximately 5 seconds. This will activate the defrost cycle and allow you to observe the operation of the defrost components.

Frequently Asked Questions

•How can I test the defrost heater?

Use a multimeter to check for continuity across the defrost heater terminals. A reading of OL indicates a faulty heater. Also check for voltage at the heater during the defrost cycle - should be 120V AC.

•Where is the defrost thermostat located?

The defrost thermostat is typically located on the evaporator coil. It is often a small, round or rectangular component with two wires connected to it. It is normally closed at low temperatures, opening when the evaporator coil reaches a certain temperature.

•What voltage should I expect at the evaporator fan motor?

You should typically see 120V AC at the evaporator fan motor when the compressor is running and during certain stages of the defrost cycle.

Whirlpool WRX735SDHZ Refrigerator: Loud Screeching Noise During Spin - Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•How can I test the defrost heater?

•Where is the defrost thermostat located?

•What voltage should I expect at the evaporator fan motor?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: