Whirlpool TruCool Refrigerator: Sensor Drift Freezing... | appliancefaults.com

Technical Background:

The Whirlpool TruCool refrigerator utilizes a thermistor in the pantry drawer to monitor temperature. The thermistor's resistance changes with temperature, and the main control unit (MCU) interprets these resistance changes to regulate the airflow to the drawer via a damper. Sensor drift means the thermistor's readings are inaccurate, causing the MCU to incorrectly control the damper, leading to overcooling and freezing. Voltage paths can be verified at the MCU connector using a wiring diagram.

Symptoms:

US homeowners have reported food freezing in the pantry drawer of their Whirlpool TruCool refrigerators, despite the main refrigerator compartment maintaining proper temperature.

Possible Causes:

Faulty Pantry Drawer Thermistor
Airflow Obstruction
Damaged Wiring Harness
Defective Main Control Board
Improper Refrigerator Leveling

Solution:

1

Disconnect the refrigerator from the 120V AC power supply by unplugging it or switching off the breaker at the breaker panel.
2

Locate the pantry drawer thermistor. It is typically behind a panel inside the drawer compartment. You may need a 1/4-inch nut driver to remove the panel screws.
3

Use a multimeter to test the thermistor resistance. At 77°F (25°C), a typical reading is around 5k ohms. Consult the service manual for the specific value.
4

Inspect the wiring harness connected to the thermistor for any signs of damage, such as frayed wires or loose connections. Repair or replace as needed.
5

Check for any airflow obstructions in the pantry drawer or vent leading to the drawer. Ensure the vent is clear of ice or debris.
6

If the thermistor tests bad, replace it with a new OEM Whirlpool thermistor.
7

After replacing the thermistor, monitor the refrigerator's performance for several days to ensure the freezing issue is resolved.

Safety Warning:

Always disconnect the refrigerator from the power source before performing any repairs. Lock Out / Tag Out (LOTO) procedures should be followed. High voltage components are present inside the appliance.

Prevention:

Regularly clean the refrigerator, including the pantry drawer and vents, to prevent airflow obstructions. Check the door seals for proper sealing to maintain consistent temperature. Periodically inspect the wiring harness for wear and tear.

Expert Tip:

To access the diagnostic mode on some Whirlpool TruCool models, press and hold the 'Temp' and 'Light' buttons simultaneously for 3 seconds. This allows you to read sensor values and run diagnostic tests.

Frequently Asked Questions

•What is the resistance value of the thermistor at different temperatures?

Consult the technical data sheet or service manual for the specific resistance values at various temperatures. The thermistor's resistance changes inversely with temperature. As the temperature increases, the resistance decreases, and vice-versa.

•How do I check the airflow to the pantry drawer?

Visually inspect the vent leading to the pantry drawer for obstructions. You can also use a tissue test: hold a tissue near the vent to see if there's sufficient airflow pulling the tissue towards the vent.

•If the thermistor and wiring are good, what else could be the problem?

If the thermistor and wiring are functioning correctly, the main control board might be defective and require replacement. This is usually a last resort after all other components have been ruled out.

Whirlpool TruCool Refrigerator: Sensor Drift Freezing Pantry Drawer - Diagnosis & Fix

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the resistance value of the thermistor at different temperatures?

•How do I check the airflow to the pantry drawer?

•If the thermistor and wiring are good, what else could be the problem?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: