It will come to help keep the controls cool inside the microwave control panel.
Exhaust fan on microwave won t shut off.
Fridgidaire microwave will not turn off check the fan.
Thus turning the fan on will keep the electronic control board from getting too hot.
The microwave has a base thermostat which is a safety device.
When it senses heat it turns on the exhaust fan.
If you are cooking on the cooktop it can sense the heat and the fan won t turn off until the thermostat cools.
When it cools down enough it will shut off.
Microwave has automatic fan ignition setting pre programmed to keep the unit components from over heating.
If pushing the stop button does not turn off your microwave try opening the door while it is still.
The exhaust fan thermostat is usually the failed component.
The exhaust fan will turn on automatically during heavy use of the surface burners on the cook top if the fan thermostat senses too mush heat.
On several models of microwaves the thermostat is super sensitive causing the exhaust to run longer than needed.