JennAir microwave displays F8, often associated with cooling or ventilation problems; unit may shut down during use.

Safety First: Unplug the microwave and allow it to cool before servicing. Do not touch high-voltage components.

• Check ventilation: Ensure the upper and rear vents are not blocked by cabinets, filters, or debris. Clean grease filters in over-the-range models with warm soapy water and dry completely.
• Listen for fan: During operation, you should hear the internal cooling fan. If F8 appears and the fan is silent, suspect a fan issue.
• Access fan motor: Remove the outer cover (for built-in/countertop) or top grille and mounting screws (for OTR models) to access the cooling fan motor.
• Inspect and test: Check the fan blades for obstructions. Spin the fan by hand; it should move freely. Use a multimeter to test the fan motor for continuity. An open winding indicates a bad motor.
• Check wiring and relay: Inspect the wiring harness from the control board to the fan. Look for loose connections or burned wires. If the fan motor tests good, the fan relay on the control board may be defective.
• Replace faulty parts: Replace the cooling fan motor if it is open or seized. If wiring and motor are good, replace the electronic control board.