Frigidaire Dryer: Lint Filter Light Stays On After... | appliancefaults.com

Technical Background:

The dryer's Main Control Unit (MCU) monitors the lint filter sensor, which detects airflow restriction. This sensor provides a voltage signal to the MCU. When the airflow is restricted (due to a dirty filter or blocked vent), the sensor's resistance changes, altering the voltage signal. The MCU then triggers the lint filter light. A faulty sensor, wiring, or MCU can cause the light to stay on even with adequate airflow.

Symptoms:

The Frigidaire dryer lint filter light illuminates and remains on even after the lint filter has been thoroughly cleaned. The dryer may otherwise function normally, but the persistent light is a nuisance and may indicate an underlying issue.

Possible Causes:

Faulty lint filter sensor.
Blocked vent duct causing back pressure.
Damaged wiring harness to the sensor.
Defective Main Control Unit (MCU).
Residue or debris affecting sensor sensitivity.

Solution:

1

Unplug the dryer from the 120V AC outlet and locate the lint filter housing.
2

Inspect the lint filter sensor (usually a small metal tab or optical sensor) for any visible damage or debris. Clean with a dry brush.
3

Check the vent duct for blockage. Disconnect the vent from the dryer and wall, and clear any lint buildup. Ensure proper airflow.
4

Use a multimeter to test the lint filter sensor's continuity. A reading outside the manufacturer's specified range indicates a faulty sensor.
5

Inspect the wiring harness connecting the sensor to the MCU. Look for frayed wires, loose connections, or corrosion. Repair or replace as needed.
6

If the sensor and wiring are good, suspect a faulty MCU. Replacing the MCU requires licensed technician assistance. Note part number and revision before ordering a replacement.
7

After repairs, plug in the dryer and test the lint filter light. Cycle the dryer to ensure the light functions correctly.

Safety Warning:

Always disconnect the dryer from the electrical outlet before performing any maintenance or repairs. Capacitors in the MCU can store a dangerous electrical charge even after the dryer is unplugged. Use caution and wear appropriate safety gear.

Prevention:

Clean the lint filter after every load. Inspect and clean the vent duct at least once a year to prevent lint buildup. Avoid using dryer sheets, as they can leave residue that affects sensor sensitivity.

Expert Tip:

On some Frigidaire models, you can enter service mode by pressing and holding the Start/Pause and Cycle Select buttons simultaneously for 3 seconds. Then navigate to the diagnostic codes and reset the lint filter warning. This may provide temporary relief but doesn't fix the underlying problem.

Follow-up Questions:

Frequently Asked Questions

•What is the typical resistance range for a working lint filter sensor on a Frigidaire dryer?

The resistance range varies by model, but typically it is between 1k and 5k ohms when the lint filter is clean and airflow is unrestricted. Consult the dryer's service manual for the exact specification.

•How do I safely discharge the capacitor on the MCU before replacing it?

Use a 20k ohm, 5-watt resistor to slowly discharge the capacitor. Connect the resistor leads to the capacitor terminals for several seconds. Verify with a multimeter that the voltage has dropped to near zero before handling the board. Wear safety glasses and gloves.

•Where can I find the service manual or wiring diagram for my specific Frigidaire dryer model?

You can usually find the service manual online by searching for your model number followed by 'service manual' or 'wiring diagram'. Websites like AppliancePartsPros or RepairClinic often have these resources available. Some manufacturers also provide them on their official websites.

Frigidaire Dryer: Lint Filter Light Stays On After Cleaning - Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the typical resistance range for a working lint filter sensor on a Frigidaire dryer?

•How do I safely discharge the capacitor on the MCU before replacing it?

•Where can I find the service manual or wiring diagram for my specific Frigidaire dryer model?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: