Error Code 21
Freezer cooling fan motor is not spinning or sending feedback
Moderate
Address soon - your appliance may not work properly
Also displayed as: LED 21 blink
What This Means
Fan motor feedback signal wire contact defect; Motor wire slipped out or disconnected; Fan motor mechanically restricted by ice or foreign object; Defective fan motor
What actually causes this:
The freezer fan motor is stuck (often from ice buildup on the blade) or its feedback wire has come loose.
First Thing to Check
Open the freezer and listen — if the fan is silent during forced operation, check for ice packed around the fan blade.
Parts Involved
How to Fix
- 1
Access self-diagnostic mode
- 2
Measure voltage at Case Connector CN2 pin #1 to pin #2 — should be between 7V and 12V during fan operation
- 3
Start forced operation (FF mode) to run the fan
- 4
Check pulse signal input at CN2 pin #3 while fan spins
- 5
If voltage fluctuates between 7–12V and 2V repeatedly, fan motor is restricted
This Error Applies To
Samsung RS27FDBTNS Series Refrigerators (2016) (2016–present)
Related Error Codes
Fridge defrost sensor has failed or lost connection
Fridge cooling fan motor is not spinning or sending feedback
Freezer temperature sensor has failed or disconnected
Ambient room temperature sensor has failed or disconnected
Fridge temperature sensor has failed or disconnected
Ice maker temperature sensor has failed or disconnected
Main board and inverter compressor board have lost communication
Freezer defrost sensor has failed or lost connection