F8
Whirlpool Dryer
Severity: ModerateWhat Does This Error Mean?
Whirlpool dryer error F8 means the moisture sensor bars inside the dryer drum are not working correctly. The moisture sensor detects when clothes are dry by measuring electrical conductivity as wet clothes pass over it. When the sensor fails, the dryer cannot tell when clothes are dry and may stop too early or run too long.
Affected Models
- WED5000DW
- WED7500GC
- WED8000DW
- WED9000YW
- WED4815EW
Common Causes
- A film of dryer sheet residue has coated the moisture sensor bars and is insulating them
- The moisture sensor wiring connection to the control board has come loose
- The sensor bars are corroded or damaged from prolonged exposure to dryer sheet chemicals
- A small foreign object is bridging or blocking the sensor bars
- The control board's moisture sensor circuit has failed
How to Fix It
-
Open the dryer door and locate the moisture sensor bars — two parallel metal strips on the inside of the door opening or on the front panel of the drum.
They look like two thin silver strips, usually about 4 to 6 inches long, positioned so clothes pass over them as they tumble.
-
Clean the sensor bars thoroughly with a cotton ball dampened with rubbing alcohol.
Dryer sheet residue builds up a waxy film on the sensors over time. This is the most common cause of F8 and the fix is completely free.
-
Run a test cycle with a load of damp towels to see if the dryer now dries normally.
If the dryer completes the cycle and the towels are dry, cleaning the sensors fixed the problem.
-
If cleaning does not help, unplug the dryer and check the wiring connection from the moisture sensor to the control board.
The wiring harness typically runs from behind the front panel. Check for loose connectors and push them in firmly.
-
If the wiring is secure and F8 persists, the sensor bars themselves may be corroded and need replacement.
The moisture sensor assembly is usually held in place by two screws. Replacement is straightforward and takes about 15 minutes.
When to Call a Professional
Moisture sensor cleaning is a free, simple fix that resolves most F8 errors. If cleaning does not work, sensor bar replacement costs $15 to $30 for the part. If the control board circuit has failed, professional board replacement runs $150 to $300.
Frequently Asked Questions
Can using too many dryer sheets cause F8?
Yes — dryer sheet residue is the number one cause of moisture sensor failure on Whirlpool dryers. The waxy coating on the sheets leaves a film on the sensor bars that acts as an insulator, preventing accurate moisture readings. Consider switching to dryer balls instead of sheets, or use fewer sheets per load.
How do I know if my dryer's moisture sensor is working?
Dampen your finger and touch both sensor bars at the same time. On a working dryer, the control panel will register moisture and the cycle timer will respond. A simple test is to run the dryer with a damp load on an auto-dry setting — if it keeps running long after the load is clearly dry, the sensor is likely coated or failed.
Is it bad to always use the timed dry setting to avoid the moisture sensor?
Using timed dry is fine and bypasses the moisture sensor entirely. However, timed dry uses more energy because it runs for a fixed time rather than stopping when clothes are actually dry. Fix the moisture sensor for better energy efficiency in the long run.