Whirlpool Dryer F03 Error — Humidity Sensor Fault Fix

What Does This Error Mean?

F03 is the humidity sensor (also called moisture sensor) — the metal strips inside the drum that detect when laundry is dry.
If they're coated with fabric softener residue, they read 'dry' even when clothes are wet.
Wipe the strips with rubbing alcohol.
If F03 persists, the sensor or its wiring has failed.

Affected Models

Whirlpool Cabrio dryer
Whirlpool Duet dryer
Whirlpool front-load dryer
Whirlpool top-load dryer

Common Causes

Sensor strips coated with fabric softener residue
Sensor wires loose or damaged
Sensor itself failed
Connector loose at the controller
Controller sensor input damaged

How to Fix It

Find the humidity sensor strips.

Open the drum and look near the lint trap area, or near the front of the drum (location varies by model).
You'll see two thin metal strips, parallel and a couple inches long.
Those are the sensor.
Easy to spot once you know what to look for.
Wipe the strips with rubbing alcohol.

Use a soft cloth dampened with rubbing alcohol.
Wipe each strip thoroughly.
Fabric softener and dryer sheet residue insulate the strips, causing the controller to read 'dry' constantly.
This is the most common F03 cause.
Try a Sensor Dry cycle.

Run an empty drum on Auto Sensor Dry for 30 seconds.
Watch the controller.
If F03 doesn't appear during that brief test, the sensor is working again.
If F03 returns immediately, the sensor or wiring has more than just residue.
Reduce fabric softener use.

Liquid fabric softener and dryer sheets are the main residue source.
Cut your softener use in half (or stop entirely) for a month.
Wool dryer balls are an alternative that doesn't leave residue.
This prevents future F03 events.
Schedule service if cleaning doesn't help.

If sensor strips are clean and F03 continues, the sensor itself or its wiring has failed.
Replacement is 30–80 USD parts plus labor.
Service-tech repair — accessing the sensor requires partially opening the drum or lint area.

Frequently Asked Questions

Will the dryer still work with F03?

Yes — Auto cycles may not work properly (ending early or running too long), but Timed Dry continues working since it doesn't depend on the sensor.
Use Timed Dry for affected loads until repair.
Set the time based on load size and fabric type.

Why does fabric softener residue build up?

Liquid softener and dryer sheets release a thin waxy coating onto everything they touch — that's how they make fabrics feel soft.
The same coating ends up on the sensor strips, the lint trap, and the inside of the drum.
Regular cleaning of all three is needed if you use softener heavily.