Siemens Fan Control Anomaly

Freezer fan runs loudly and continuously even when the compressor is off.

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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 fan relay or transistor on PCB, Incorrect door switch signal, Firmware logic issue, Shorted fan wiring causing backfeed

How to Fix / Troubleshooting

Safety: Unplug the freezer before accessing the fan or control board.

  • 1. Verify door switch: Ensure the door switch correctly signals open/closed; replace if faulty.
  • 2. Inspect fan wiring: Check for wiring modifications or damage that could cause constant power to the fan.
  • 3. Power reset: Unplug for 10–15 minutes, then reconnect and observe if fan behavior normalizes.
  • 4. Replace main PCB: If the fan remains on continuously and wiring is correct, the fan driver on the PCB may be stuck and the board should be replaced.

Note: A constantly running fan increases noise and may cause excessive drying of food but is less critical than cooling failures.

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Repair Difficulty

Hard 4/5

Required Part

Main Control Board
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