F3T Moderate Moderate DIY

Whirlpool Microwave F3T — Exhaust Fan Thermostat Fault

Whirlpool Microwave · Error code F3T

What F3T Means

The exhaust fan thermostat is reading outside the expected range (below 41°F / 5°C or above 140°F / 60°C). The vent fan over the cooktop won't kick on automatically in response to heat.

Symptoms

  • F3T on the display
  • Vent fan doesn't auto-start when the cooktop below is hot
  • Microwave cooks normally otherwise

Common Causes

1
Failed exhaust fan thermostat

Cycles open or shorts with age.

2
Wiring open at the thermostat

Inspect the harness in the vent path.

3
Ambient temperature truly out of range

If the kitchen is freezing or above 140°F, the code is valid — let the unit reach normal temp.

How to Fix It

  1. Confirm normal kitchen temperature (above 41°F, below 140°F). Let the microwave equalize.
  2. Power down at the breaker for 1 minute and retest.
  3. Unplug the unit, locate the exhaust fan thermostat per the tech sheet, and check continuity at room temp.
  4. Replace the thermostat if it reads open or wildly out of spec.
  5. If a new thermostat doesn't clear F3T, suspect the appliance control board.

Parts You May Need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

Common replacement Whirlpool microwave exhaust fan thermostat View on Amazon→

More Whirlpool Microwave Codes

AccuPop Fail AccuPop Fail — Popcorn Sensor Fault Demo Demo Mode — Not Heating Door Door / Open Door Closed — Safety Reminder F1E4 F1E4 — Appliance Control Board Fault F1E5 F1E5 — Inverter Internal Fault F2 F2 — Keypad / Control Fault

All Whirlpool codes → All microwave codes →

Verified against manufacturer documentation: applianceaid.com

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.