Diagnosis
The most common reason the interior light fails on this model is a burned-out halogen bulb. If a new bulb doesn't work, the issue is typically a failed door switch micro-switch that signals the control board to turn the light on, or less commonly, a problem with the control board itself.
How to Fix It
- Unplug the microwave for safety.
- Open the door and locate the bulb cover inside the top of the cooking cavity. It is usually a rectangular plastic or glass shield.
- Gently press and slide or turn the cover to remove it, revealing the bulb socket.
- Replace the old bulb with a new 20-watt Halogen T4 (JCD type) bulb. Use a cloth or gloves to handle the new bulb; skin oils can cause hotspots and shorten its life.
- Reinstall the cover, plug the unit in, and test the light by opening the door and pressing the light button on the control panel.
If That Didn't Work
The door switch assembly has multiple micro-switches. The specific one for the light may be stuck open or failed. You will need to test the switches with a multimeter for continuity or replace the entire switch assembly (part # DE61-00657A is common for this series). This requires removing the outer casing, which involves disconnecting power and carefully noting wire locations. If the switches test fine, the control board may have a failed relay for the light circuit, necessitating board replacement.
Heads Up
Always disconnect power before any internal repair. The bulb and its surrounding components can retain extreme heat long after use—allow the microwave to cool completely. When handling the new halogen bulb, avoid touching the glass directly.