What F3 (Kenmore microwave) Means
F3 on a Kenmore microwave reports a thermistor short detected after cooking: the sensor temperature did not fall once the cycle ended, which is behaviour a healthy cavity and a healthy sensor should not produce.
Common Causes of F3 (Kenmore microwave)
- A thermistor shorted internally
- Grease-clogged vent filters trapping heat in the cabinet
- A cooling fan no longer running
🔧 One Safe Check You Can Try
Unplug the unit for a few minutes to reset it, and check that the vents on an over-the-range model are not blocked by grease-laden filters, since restricted ventilation genuinely slows cooling.
⚠ Why You Shouldn't Go Further Than That
- A microwave housing is never opened by an owner, because the high-voltage capacitor holds a dangerous charge even unplugged.
- A cavity that genuinely stays hot after cooking may point at a cooling or ventilation fault, which is worth taking seriously above a cooking surface.
- Grease-laden filters above a range are a fire-safety matter in their own right, quite apart from this code.
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.