What F3T3 Means
Over-the-Range Microwave: KitchenAid publishes for F3T3 "There may be a problem with the Hood Temperature Thermistor or the associated wiring." The hood thermistor is the sensor that watches how hot the underside of the appliance is getting from the cooking surface beneath it. On over-the-range units that reading is what triggers the vent fan to protect the appliance when a pan below is running hard. A fault against it means that protection has lost its input.
Common Causes of F3T3
- A hood temperature thermistor failed or out of range
- Wiring between the hood thermistor and the control
- A control input no longer reading the sensor
🔧 One Safe Check You Can Try
Switch off the cooking surface underneath and let it cool before you stand at the appliance at all - an over-the-range unit puts your forearms directly above a range, and a burn from a hot hob is the injury that actually happens while people are troubleshooting a microwave. Then power the unit down by switching off the circuit breakers for one minute, power it back up, watch the microwave for one minute to see whether the code returns, and verify the microwave operates. Until it is seen to, avoid heavy or prolonged cooking on the surface directly beneath it.
⚠ Why You Shouldn't Go Further Than That
- The hood sensor is what lets the appliance protect itself from the range underneath it, so an appliance that cannot take that reading is sitting above a heat source without its usual warning.
- The high-voltage capacitor inside a microwave can hold a lethal charge after the unit is unplugged and the display is dead, so the inside of the cabinet is not an owner check at any point in this process, whatever the code turns out to mean.
- Getting inside an over-the-range microwave means unbolting it from the cabinet above and lifting it clear of the range below, which needs two people and a clear cooktop before anything else.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.