How to Fix / Troubleshooting

Safety: Disconnect power before servicing the exhaust system.

Check controls: Verify that the fan is not in automatic mode only (some models run the fan automatically when hot).
Listen for motor: If the fan hums but does not spin, the exhaust fan motor may be seized or obstructed.
Inspect blower: Remove the top grille and access the blower assembly. Check for debris or grease buildup on the blower wheel.
Test motor: Use a multimeter to check continuity of the fan motor. Replace if open or seized.
Control issue: If the motor tests good, the fan speed switch or control board relay may be defective.

Microwave exhaust fan on an over-the-range Monogram unit does not run or runs only on some speeds.

Possible Causes