On GE over-the-range models, a non-stop vent fan usually points to auto-cooling, clogged filters, a stuck keypad, or a failed thermostat or relay.
Why Your GE Microwave Vent Fan Keeps Running
Over-the-range units include two fans: an internal cooling fan for electronics and the range-hood vent that moves air over the cooktop. The hood fan can start by itself when the cooktop heats the control area. A thermostat near the panel triggers the fan and keeps it running until the oven cools down. You can’t switch it off while that protection is active. GE explains this automatic fan feature, including the control-area temperature it watches. When heat isn’t the trigger, other faults are more likely.
Quick Diagnosis Guide
| Symptom | Likely Cause | First Move |
|---|---|---|
| Fan starts by itself while you’re boiling or frying | Heat at the sensor | Let it cool 10–30 minutes; use lower burner heat next time |
| Fan runs long after the cooktop is cool | Grease or charcoal filters blocked; weak airflow | Clean or replace filters; run on HIGH for a minute to clear steam |
| Fan ignores VENT keys | Stuck keypad; control lock; relay stuck on the board | Power-cycle; try all vent speeds; look for CONTROL LOCK on display |
| Fan turns on the instant power is applied | Thermostat shorted closed or relay welded | Unplug and schedule service; part likely needs replacement |
| Fan stops only when the door is open | Control logic fault | Two-minute reset; service if no change |
GE Microwave Vent Fan Not Turning Off: Quick Checks
1) Let It Cool
If the fan kicked on during cooktop use, give it time. The auto-vent shields the controls and clears steam. Opening a window or switching the fan to HIGH for a minute moves hot air away faster. GE notes that you can’t disable auto-vent during a heat event; it stops when the control area cools below its target (GE support details).
2) Toggle The Vent Properly
Press VENT FAN to cycle High → Low → Off. Some panels require stepping through each speed. Try every speed once, then press Off. If buttons feel sticky, wipe them dry; moisture on the touch panel can act like a held key.
3) Do A Safe Power Reset
Turn the breaker off or unplug the oven for two minutes. Restore power, then test the vent keys again. This clears a frozen control and drops any latched relays. If the fan blasts the instant power returns, jump ahead to the thermostat and relay section.
4) Clear The Filters
Poor airflow raises internal temperature, which keeps the fan running. Remove the metal grease filters and wash with hot, soapy water or in the dishwasher. If your unit recirculates instead of venting outside, the charcoal filter traps odors and fine mist; replace it if it’s older than six months or loaded with grease. With clean filters, airflow improves and the auto-cool cycle ends sooner.
5) Check For Control Lock Or Demo Modes
If the display shows LOCK or a padlock icon, Control Lock is on. Vent keys might be ignored until the lock is cleared. Hold CLEAR/OFF or the LOCK icon for three seconds to toggle it on many models. If your panel uses SETTINGS, look for a lock entry and turn it off.
When The Fan Truly Sticks On
If the kitchen is cool and filters are clean, the fan shouldn’t run forever. These faults keep it spinning:
- Thermostat stuck closed. The thermostat near the control area closes around a target temperature and reopens as it cools. If it fails closed, the board thinks it’s hot all the time.
- Welded vent-fan relay. A relay on the control board switches the hood motor. Heat or a surge can weld the contacts shut so the motor never loses power.
- Keypad false input. A wet, damaged, or misaligned membrane can send a constant “fan high” command.
Safe Tests For Skilled DIYers
Power off at the breaker and wait several minutes. Remove the top grille and the single screw holding the control panel to peek behind it. With the unit still disconnected:
- Thermostat continuity. Pull one wire from the thermostat and check with a multimeter. At room temperature it should read open. If it reads closed, replace it.
- Relay sound check. Restore power briefly with the fan stuck on. Press each vent speed. If you never hear a relay click, the contacts may be welded shut. Cut power again.
- Keypad ribbon reseat. Disconnect and reseat the flat ribbon cable from the keypad to the board. If the fan behaves differently after reseating, the panel may be the culprit.
Step-By-Step Fixes You Can Try Now
1) Give It A Cool-Down Window
After heavy cooktop use, set a timer for 15 minutes and step away. If the fan stops on its own inside that window, you’ve confirmed normal auto-cool behavior. Use lower burner settings next time or switch the fan on sooner to vent steam before it builds.
2) Deep-Clean The Air Path
Wash grease filters, wipe the vent housing, and make sure the damper flap isn’t stuck. If you recirculate, pop in a fresh charcoal filter. A clear path lowers temperatures near the control area and shortens fan run-time.
3) Reseat Or Dry The Keypad
Wipe any moisture from the touch panel. If steam hit the panel, leave the door open for ten minutes and point a small fan at the controls. Once dry, try the vent keys again.
4) Hard Reset
Kill power for five minutes to discharge the board. While you wait, press and hold the VENT key for five seconds (with power off) to bleed static from the keypad. Restore power and retest.
5) Thermostat Replacement (Skilled DIY)
With the model number in hand, order the correct hood-fan thermostat. It’s usually behind the control panel or on top of the cavity. Move one wire at a time to the new switch. If the old part was stuck closed, the fan should behave normally again.
6) Control Board Or Relay (Pro Fix)
If the relay is welded or the board is shorted, replace the board. A microwave contains high-voltage parts, so this repair needs a licensed technician.
Parts, Location, And DIY Difficulty
| Part | What It Does | DIY? |
|---|---|---|
| Grease filter | Catches cooking grease so air can move | Yes |
| Charcoal filter | Deodorizes when venting indoors | Yes |
| Thermostat | Tells the board the control area is hot | Maybe, if handy |
| Keypad panel | Sends your button presses | Maybe, careful handling |
| Control board | Switches the fan through a relay | No, pro job |
Model Tips And Settings
- Some GE models label the vent switch VENT, VENT FAN, or FAN HI/LO/OFF. Cycle through each step; Off usually sits after Low.
- Auto-vent can’t be disabled. It’s a safety feature tied to a thermostat near the control panel. On GE guidance, that sensor kicks in around the upper range they specify on the automatic fan feature page.
- If your unit vents outdoors, a stuck roof or wall damper can trap heat. Make sure it swings freely and the duct isn’t crushed.
- Replace the charcoal filter on schedule so recirculating units breathe well, which shortens auto-cool cycles.
When To Call A Technician
- Fan runs instantly at plug-in with a cool kitchen.
- Thermostat reads closed at room temperature.
- Fan only stops when you open the door or kill power.
- Keypad works for everything except the vent keys.
- There’s a burnt smell, arcing, or the breaker trips.
If your model shows fan and turntable activity by itself, GE has a page on what to check first: Microwave starting on its own.
Prevention: Keep The Fan From Running Non-stop
- Start the fan before you heat oil or boil water.
- Keep a clear path: clean grease filters monthly; swap charcoal filters twice a year.
- Leave a little space above back burners so pots don’t force steam straight into the control panel.
- Aim for gentle simmer instead of a rolling boil under the microwave.
- Wipe moisture off the touch panel after steamy cooking.
- Once you finish at the cooktop, run the fan on High for one minute, then press Off.
Fast Troubleshooting Script
- Is the cooktop or control area hot? Cool the kitchen.
- Filters dirty? Clean or replace.
- Panel locked or wet? Unlock and dry.
- Power-cycle for two to five minutes.
- Still stuck? Test the thermostat or book service.