Microwave displays E09 and the interior light does not turn on when the door is opened.

Safety first: Unplug the microwave before replacing the lamp or accessing switches.

• Step 1 – Check door operation: Open and close the door and observe if the display reacts (e.g., shows 'door' or standby). If the display does not change, the door sensing switch may be faulty.
• Step 2 – Replace lamp (if only light is out): Access the lamp cover (often behind a grille or side panel). Remove the cover, unscrew the old bulb, and install a Bertazzoni-compatible microwave lamp of the same wattage and base type.
• Step 3 – Inspect lamp socket: Check for heat damage or loose connections at the lamp holder. Replace the socket if burnt or cracked.
• Step 4 – Door switch test: With power disconnected, test the door sensing switch with a multimeter for proper continuity when the door is opened/closed. Replace if defective.
• Step 5 – Control board: If the lamp, socket, and switch are good but E09 persists, the lamp circuit on the control board may be open and the board will need replacement.