Haier Door interlock switch miswiring or welded relay

Microwave light, fan, and turntable run when door is closed, even without pressing Start

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.

Possible Causes

Stuck or welded relay on control board, Misadjusted or shorted door switch, Incorrect previous repair wiring

Danger: A microwave that runs with the door closed but not commanded can be unsafe. Unplug it immediately.

Do not use: Leave the microwave unplugged until repaired.
Inspect door switches (advanced): A technician should check the door switch assembly for a stuck switch and verify correct wiring.
Control board check: If switches are correct, the main control board relay may be welded closed and must be replaced.

Professional Required 5/5

Main Control Board or Door Switch Assembly

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