Microwave interior light does not come on, but the unit heats and operates normally.

Safety first: Unplug the microwave before replacing the lamp. Avoid touching high-voltage components.

Step-by-step checks:

• 1. Access lamp: On many Grundig models, the lamp is accessible from the side or top after removing the outer cabinet or a dedicated lamp cover.
• 2. Inspect bulb: Check if the filament is broken or the bulb is darkened. Replace with the correct wattage and type specified by Grundig.
• 3. Check holder: Ensure the lamp is seated firmly and the holder contacts are not corroded.

If a new lamp does not work, the lamp circuit on the control PCB may be faulty and require professional repair.