Frigidaire · Microwave Moderate

Cooling Fan — Frigidaire Microwave 'Cooling Fan' / Fan-runs-after-cooking — Vent fan stuck on

Many over-the-range Frigidaire microwaves run the vent/cooling fan automatically when the cabinet gets hot (typically above ~158°F / 70°C). If it runs constantly or will not shut off, the thermal sensor or control is calling for cooling indefinitely.

Keep using it?
Yes, with caution
DIY difficulty
Moderate
Verified against
frigidaire.com ↗

How to fix it

  1. Stop using the cooktop and wait 15–30 minutes — if fan stops, it was normal auto-cool.
  2. If it never stops, unplug for 5 minutes and re-test.
  3. Test the thermal cutout / thermistor on top of the microwave per the tech sheet (should open at room temp on cutout types, or read normal resistance on thermistor types).
  4. Replace the thermal sensor if it does not open / reads shorted.
  5. If sensor is good, replace the control board.

Why it happens

Typical signs: Vent fan runs nonstop, even when microwave is off · Fan kicks on minutes after a cycle · Cannot turn fan off from Vent Fan button

  • Heat from cooktop below triggering auto-cool Normal behavior on OTR units — fan runs until cabinet cools.
  • Stuck-closed thermal sensor Sensor reads hot even after cabinet cools.
  • Failed control board Board commands fan on continuously.

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.

  • Frigidaire microwave thermal cut-off / thermostat Common replacement
    Amazon →
  • Frigidaire microwave thermistor Common replacement
    Amazon →

More Frigidaire microwave codes

Child Lock 'Lock' / 'L' — Child lock engaged Demo 'Demo' / 'd' — Showroom demo mode on door 'door' message — Door not fully closed F1 F1 — Control board / thermistor open F2 F2 — Keypad / Control Board Input Fault F3 F3 — Stuck key on touchpad

All Frigidaire codes → All microwave codes →

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: frigidaire.com.