The answer up front
Oven code F3H is the control reporting that the reading arriving from the humidity thermistor and its wiring fell outside the band the control is built to trust. You can clear the code and start again, but heating is held back until the reading comes back inside its window.
The code and what the manufacturer documents for it
Reference| Code | Documented meaning |
|---|---|
| F3H | There may be a problem with the Humidity Thermistor or the associated wiring. |
What the appliance does alongside the code
- The fault comes and goes with temperature — An intermittent connection opens as the metal expands and closes again when it cools, which is why the code often arrives part-way through a long cycle.
- The fault follows the weather or the time of day — A cold kitchen and a hot one put a marginal probe on opposite sides of its limit, which is why some of these arrive seasonally.
- NEAR MISS - nothing heats and no code shows at all — That is a power or element fault rather than a reading fault, and it belongs on the page for that symptom.
Causes in the order they actually occur
- A loose or corroded connector at the thermistor — Ranked first because it is the failure that needs no part: the probe is fine, the joint carrying its signal is not, and heat cycling at the back of the cavity is what works a pin loose.
- The board input itself — Last, and deliberately last: an input stage fails far less often than the circuit in front of it, and replacing it first is the expensive way to find out the connector was loose.
The check order this code implies
- Power the machine down fully and see whether the code returns — Costs nothing and separates a latched one-off read from a live fault.
- Look at the connector at the thermistor before anything is measured — Seated, clean and tight is a five-second answer to the most likely cause.
What you can do without tools
- Let the cavity reach room temperature before anything else — A hot resistance reading means nothing, and a hot cavity is the reason half of these codes cannot be diagnosed on the spot.
About 45 min
- Run the shortest cycle the appliance offers and watch for the code — A short cycle that stays clean while a long one fails tells a technician the fault is thermal.
About 20 min
- STOP HERE if the next step is a meter across the probe terminals — That means a panel off and a connector back-probed, which is where an owner check ends and a service call begins.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before any panel comes off; a capacitor can hold a charge after the power is off. Everything in the procedure above stays outside the cabinet for that reason.
The point at which you call
Call once the code survives a full power-down: a repeatable reading fault is a probe, a harness or a board, and telling those three apart needs a meter and the resistance table for that model line. There is one case that does not wait for any of that.
Codes next to this one
The scope of this reading
Written for the model lines that use this probe on this cavity, this page describes what the code means and how to work through it, nothing more specific. A family-level or model-level page, where one exists, is the better answer for your unit - the index below lists what is available.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
