E12
Westinghouse Door Interlock Monitor Circuit Error

Microwave shows E12 and the interior light remains on even when the door is closed; unit may refuse to 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

Failed monitor switch stuck closed,Incorrectly installed door switches,Shorted wiring in door switch harness,Defective control board door input circuit

How to Fix / Troubleshooting

Safety first: Unplug the microwave immediately if the light stays on with the door closed. Do not operate until repaired.

Basic checks:

  • 1. Inspect door closure: Ensure nothing is obstructing the door and that it latches fully.

Advanced steps:

  • 2. Access door switch assembly: Remove the outer cover and locate the primary, secondary, and monitor switches.
  • 3. Verify correct switch orientation: Compare switch positions and wiring to the service diagram. Incorrect installation can cause E12.
  • 4. Test monitor switch: With a multimeter, confirm the monitor switch opens and closes correctly as the door is operated. Replace if stuck or intermittent.
  • 5. Inspect harness: Look for pinched or shorted wires between switches and the control board.

If the wiring and switches are correct but E12 persists, the control board may be misreading the door circuit and require replacement.

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Repair Difficulty

Hard 4/5

Required Part

Monitor Door Switch
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