Grundig Door Switch / Monitor Circuit Miswiring or Failure

Microwave interior light, fan, and turntable run when the door is closed, even without pressing START.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Stuck primary door switch, Miswired door switches after previous repair, Shorted control relay, Damaged control PCB

How to Fix / Troubleshooting

Danger: This is a serious safety fault. Unplug the microwave immediately and do not use it until repaired.

Step-by-step checks (for experienced DIYers only):

  • 1. Inspect door switches: Remove the cabinet and check that each door switch operates freely and is not physically stuck.
  • 2. Verify wiring: Compare the wiring of the door switches to the wiring diagram (often on the inside of the cabinet). Correct any miswired connections.
  • 3. Check control relay: Inspect the control PCB for a relay that may be welded closed (burn marks or melted casing).

Because of the risk of microwave radiation leakage, if you are not fully confident, have a professional service center repair and test the unit with proper leakage equipment.

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Repair Difficulty

Professional Required 5/5

Required Part

Door Interlock Switch Set
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