GE Monogram Oven Error F9: Cooling Fan Speed Fault

The Logic Verdict

I watched Fix It Felix replace the broken door lock that every forum blames for F9, only to have the code pop right back up. The real fault lived behind the back panel: a grease-soaked reed switch that monitors the cooling fan next to a fan motor full of dust. He cleaned nothing—he swapped in a fresh switch, a new lower cooling fan, and even an RTD sensor, then ran the oven up past 225°F with no error. If your Monogram throws F9 the moment it warms up, skip the control board rabbit hole and go straight to the fan circuit.

What It Means

On GE Monogram wall ovens, F9 is the logic board screaming that the cooling fan never hit speed. The control waits for the fan-speed sensor (a reed switch) to see airflow whenever the bake elements fire. If the fan drags, is unplugged, or the switch never closes, the oven shuts everything down and posts F9 to protect the electronics.

Common Causes

• Fan speed switch full of grease. Felix’s reed switch literally fell apart in his hand—its glass capsule was coated in oil so the board never saw pulses.
• Cooling fan that can’t spin up. Dust, melted plastic pins, or a failing motor bog the blower until the sensor reports no airflow.
• Wiring mishaps around the fan cover. After latch repairs or self-clean cycles, the harnesses near the fan cage get disturbed; if a connector is loose, the board assumes the fan is dead.

Step-by-Step Fix

1. Kill power and confirm the latch. Felix still replaced the melted door lock because it was physically broken. Swap the latch if needed, but understand that Monogram F9 codes persist even with a new lock.
2. Pull the oven and remove the back panel. Disconnect power at the breaker, slide the oven far enough out of the wall to reach the rear cover, and back out the perimeter screws—including the two hidden ones near the bottom trim. Lift the sheet-metal panel off to expose the blower cavity and control board.
3. Access the fan and reed switch. Remove the small aluminum heat shield (two screws) over the cooling fan. The fan comes out with three screws; once it’s free you can see the tiny reed-switch board sitting directly in front of the blades. If the glass capsule is cracked or coated in grease, replace it. You can try to clean it with alcohol, but Felix showed why replacement is faster.
4. Install the new cooling fan. Drop the replacement fan in the same orientation and transfer the little green circuit board if your OEM fan requires it. Make sure the harness seats fully and that nothing drags on the impeller.
5. Snake in a fresh RTD sensor (optional but smart). His customer also complained about temperature swings, so he clipped the ties holding the RTD harness, pulled the old probe into the cavity, ran the new sensor lead from the oven interior, and reconnected it at the control board. If your oven has been overheating, this is cheap insurance while it’s already apart.
6. Button up and test to temperature. Reinstall the fan shield and rear cover, restore power, and run the oven past the point where it used to fail (Felix targeted 300°F). You should hear the cooling fan humming steadily. If F9 returns, double-check the reed-switch connector and wiring back to the control board.

Parts & Tools

• GE WB24T10045 reed switch / fan speed sensor
• GE WB26X35089 wall-oven lower cooling fan

Watch the Fix