Safety first: Disconnect power before opening the interior panels.

Check for airflow: With the door open and the unit running (before unplugging), listen for the evaporator fan. If silent and no air is blowing from the vents, suspect the fan or ice blockage.
Inspect for ice: Unplug the freezer and remove baskets and the internal rear panel. If the fan is encased in ice, perform a full manual defrost (door open, towels on floor) until all ice is gone.
Spin the fan by hand: After defrosting, gently spin the fan blades. If stiff or jammed, the motor is likely failing and should be replaced.
Check wiring: Inspect the fan connector and harness for corrosion or broken wires. Reseat the connector to the fan and to the main board if accessible.
Replace fan motor if needed: Remove mounting screws, disconnect the old motor, and install a compatible De Dietrich evaporator fan motor. Ensure the fan blades are correctly oriented and not rubbing on the shroud.
Reassemble and test: Refit the rear panel, restore power, and confirm that the fan runs and AL05 clears.

Freezer shows AL05; fan noise may stop and frost builds up on the evaporator.

Possible Causes