KitchenAid Over-the-Range Microwave Code F3H: humidity thermistor reading

What F3H means

On KitchenAid over-the-range microwaves such as the KMHS120ESS or KHMS155LSS, F3H indicates there may be a problem with the humidity thermistor, or the wiring to it. This part helps sensor cooking judge steam from food. When its reading is lost, sensor programs stop and the code may appear on the display.

Common causes of F3H

Humidity thermistor failing
Wiring to the thermistor loose
Moisture or grease affecting the part

✓ One safe check you can try

1. Press Cancel and let the cavity air out with the door open. 2. Wipe the cavity dry. 3. Wait one minute with the plug out, then reconnect. 4. Use a timed program instead of sensor cooking. 5. If F3H returns, call us.

! Why to stop there

The part is inside the cabinet and requires disassembly
A reading test tells us whether the thermistor or the wiring has failed
Written price first, and the repair is under a 30-day warranty

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Microwave codes

Probe or Insert ProbeKitchenAid Combination Microwave Message "Probe" or "Insert Probe": Seat the meat probe in its jack PUSH or PSHKitchenAid Built-In Microwave Message PUSH or PSH: The oven is waiting for Start Registration ErrorKitchenAid Over-the-Range Microwave Message "Registration Error": Check the home network and try again Sabbath, Sab, 5Ab, or 5A6KitchenAid Built-In Microwave Display Sabbath, Sab, 5Ab or 5A6: Sabbath Mode is on SEKitchenAid Over-the-Range Microwave Code SE: Keypad or user interface problem F4 E9KitchenAid Combination Microwave Code F4 E9: Microwave inverter output problem F9 or F9E0KitchenAid Built-In Microwave Code F9 or F9E0: Check the electrical connection after installation Press Cancel to ResetKitchenAid Built-In Microwave Message "Press Cancel to Reset": Clear it, then reset power if Call Service shows

F3HF3H questions

What does the humidity thermistor do?

It helps the oven detect steam so sensor cooking knows when food is done.

Are F3H and F3H1 the same part?

F3H names the humidity thermistor, while F3H1 names the humidity sensor. The parts are close cousins and a technician tests both.

Can I keep microwaving?

Timed cooking should still work. Avoid the sensor settings until it has been checked.