Microwave interior light does not turn on when cooking or when the door is opened, but the unit still heats.

Safety first: Unplug the microwave before replacing the lamp.

Steps:

• Locate lamp cover: On many Clatronic models, the cavity lamp is accessible from the rear or side behind a small cover.
• Remove cover: Unscrew the cover and carefully remove it.
• Replace bulb: Remove the old lamp and replace it with the exact type and wattage specified for your Clatronic model (usually a special microwave-rated bulb).
• Check socket: Ensure the lamp socket contacts are clean and not burned.
• Reassemble and test: Refit the cover, plug in, and test door opening and a short cook cycle.

Warning: Use only microwave-rated lamps; incorrect bulbs can overheat or fail prematurely.