Whirlpool Duet Dryer: Moisture Sensor Not Detecting Dry... | appliancefaults.com

Technical Background:

The Whirlpool Duet dryer uses a moisture sensor, typically two metal bars inside the drum, to detect the moisture level in the clothes. These bars work by measuring the resistance between them. As the clothes dry, the resistance increases. The MCU interprets this resistance change and terminates the drying cycle when a certain threshold is reached. A small load may not create enough contact for the sensor to accurately measure moisture, or a buildup of fabric softener residue can affect the sensor's readings.

Symptoms:

The dryer runs, but the clothes remain damp even after a full cycle, especially with small loads. The dryer does not seem to sense that the clothes are dry and doesn't advance to the cool-down phase.

Possible Causes:

Dryer vent is partially blocked, reducing airflow.
Moisture sensor bars are dirty or corroded.
The dryer is overloaded, preventing proper tumbling and sensing.
Faulty moisture sensor.
Wiring harness issue between the sensor and the control board.
Main Control Unit (MCU) malfunction.

Solution:

1

Unplug the dryer from the 120V AC outlet and ensure Lock Out/Tag Out (LOTO) procedures are followed.
2

Inspect and clean the moisture sensor bars inside the dryer drum with a Scotch-Brite pad.
3

Check the dryer vent for obstructions. Disconnect the vent from the dryer and the wall. Use a vent brush to remove lint. Reconnect and ensure there are no kinks in the vent hose.
4

Access the dryer's control panel and locate the moisture sensor connector on the MCU. Use a multimeter to test the continuity of the sensor wires.
5

With the dryer unplugged, inspect the wiring harness from the sensor to the control board for any damage or loose connections. Repair or replace as needed.
6

If the wiring and sensor test okay, suspect a faulty MCU. The MCU may require replacement.
7

After repair, run a test cycle with a small load to confirm the issue is resolved.

Safety Warning:

Disconnect power to the dryer before performing any repairs. Electrical shock hazard exists. Always use proper Lock Out/Tag Out (LOTO) procedures before starting any work.

Prevention:

Clean the lint filter after every load. Periodically inspect and clean the dryer vent. Avoid overloading the dryer. Use dryer sheets sparingly, as they can leave a residue on the moisture sensor.

Expert Tip:

Enter service mode by pressing and holding the 'Start' and 'Control Lock' buttons simultaneously for 3 seconds. This allows you to run diagnostic tests and view error codes.

Frequently Asked Questions

•How do I access the moisture sensor to clean it?

Unplug the dryer. Open the dryer door. The moisture sensor bars are typically located at the front, inside the drum. Use a Scotch-Brite pad to gently clean the surface of the bars, removing any lint or residue.

•What resistance value should I expect to see across the moisture sensor when it's dry?

A dry moisture sensor should read an open circuit or very high resistance (megohms). When wet, the resistance will drop significantly (kilohms or less), signaling the presence of moisture to the control board.

•How can I tell if the vent is properly connected?

Ensure the vent hose is securely clamped to both the dryer exhaust and the wall outlet. The hose should be as short and straight as possible, without any kinks or sharp bends. Use foil or metal duct tape to seal any gaps for an airtight connection.

Whirlpool Duet Dryer: Moisture Sensor Not Detecting Dry Clothes - Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•How do I access the moisture sensor to clean it?

•What resistance value should I expect to see across the moisture sensor when it's dry?

•How can I tell if the vent is properly connected?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: