Diagnosis
The convection fan motor has failed or its power connection is loose. It's a common failure point on the early combo models.
How to Fix It
Unplug the griddle. Remove the two screws on the air fryer's rear access panel. Pull the panel off. Locate the fan motor on the left side. Check the white wire connector going to it. Push it on firmly. Plug the unit in and test. If the fan still doesn't run, the motor needs replacement.
If That Didn't Work
The control board might not be sending power to the fan. Use a multimeter to check for 120V AC at the fan connector when the air fryer is on. No power means a bad board.
Heads Up
Don't run the air fryer without the fan working. It will overheat the cavity and can damage the heating element or wiring.