Frigidaire Dryer Moisture Sensor Not Detecting Dry... | appliancefaults.com

Technical Background:

The Frigidaire dryer moisture sensor works by measuring the electrical resistance across the clothes as they tumble. The Main Control Unit (MCU) sends a low-voltage signal (typically 5V DC) to the sensor bars. When the clothes are wet, they conduct electricity more easily, resulting in a lower resistance. As the clothes dry, the resistance increases. The MCU monitors this resistance and uses it to determine when the clothes are dry and shut off the dryer. A faulty sensor, wiring, or control board can disrupt this process.

Symptoms:

Homeowners report the dryer runs for an extended period but clothes remain damp, or the dryer shuts off prematurely even when clothes are still wet. The auto-dry or sensor-dry cycle seems to be malfunctioning.

Possible Causes:

Faulty moisture sensor
Wiring issue between sensor and control board
Defective dryer control board (MCU)
Grounding issue
Lint buildup on the sensor bars
Incorrect dryer settings

Solution:

1

Unplug the dryer from the outlet or turn off the breaker. Lock Out Tag Out (LOTO).
2

Locate the moisture sensor bars inside the dryer drum (usually near the lint filter). Typically secured with a 1/4-inch nut driver.
3

Clean the sensor bars with a damp cloth and mild detergent to remove any lint or residue. Ensure they are completely dry before reassembling.
4

Use a multimeter to test the continuity of the moisture sensor. A normal reading is typically between 10k and 100k ohms, depending on humidity. If the reading is out of range, replace the sensor.
5

Inspect the wiring harness connecting the sensor to the dryer control board for any damage or loose connections. Repair or replace as needed. Check for 5V DC signal from the MCU.
6

Check the dryer's grounding. A poor ground can affect the sensor's readings. Verify ground at the dryer chassis to the breaker panel.
7

If the above steps don't resolve the issue, the dryer control board (MCU) may be faulty and require replacement or licensed technician repair. A new board may require programming.

Safety Warning:

Always disconnect the dryer from the power source (unplug or turn off the breaker) before performing any repairs. Dryers operate on 240V AC electricity, which can be dangerous. Use Lock Out Tag Out procedures.

Prevention:

Regularly clean the lint filter after each load. Periodically inspect and clean the moisture sensor bars to prevent lint buildup. Ensure proper dryer venting to promote efficient drying.

Expert Tip:

Many Frigidaire dryers have a diagnostic mode. To access it, consult the service manual for your specific model. It often involves pressing a specific sequence of buttons on the control panel. This mode can display error codes related to the moisture sensor.

Follow-up Questions:

Frequently Asked Questions

•How do I identify the moisture sensor on my specific Frigidaire dryer model?

Refer to the dryer's service manual or parts diagram. The moisture sensor is typically located inside the drum, near the lint filter housing. It usually consists of two metal bars or strips.

•What is the typical resistance range for a working moisture sensor?

The resistance range can vary depending on the model and ambient humidity. However, a general range is between 10k ohms and 100k ohms when the sensor is dry. Consult the service manual for the specific range for your dryer.

•Where can I find a replacement moisture sensor for my Frigidaire dryer?

You can purchase a replacement moisture sensor from appliance parts retailers, both online and in brick-and-mortar stores. Be sure to have your dryer's model number handy to ensure you get the correct part. Sears Parts Direct, RepairClinic, and AppliancePartsPros are some common sources.

Frigidaire 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 identify the moisture sensor on my specific Frigidaire dryer model?

•What is the typical resistance range for a working moisture sensor?

•Where can I find a replacement moisture sensor for my Frigidaire dryer?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: