Error Code F-DEF
Freezer defrost heater circuit failure - defrosting did not complete within maximum allowed time
Critical
Stop using immediately - risk of damage or safety issue
Also displayed as: -23 deg C LED Lamp blinking
What This Means
Separation or disconnection of defrost heater housing connector; Wire cut or short circuit in defrost heater circuit; Open or shorted thermal fuse (109 deg C or 110 deg C cut-off); Defective bimetal thermostat (Off: 60 deg C, On: 40 deg C); Defective defrost sensor; Heater element failure
What actually causes this:
Burned-out defrost heater, blown thermal fuse, stuck bimetal, or disconnected wiring in the freezer defrost circuit
First Thing to Check
Disconnect CN70 and measure resistance between pins 3 and 1 to determine open or short condition
Parts Involved
How to Fix
- 1
Enter Self-Diagnosis mode by pressing Freezer + Fridge buttons simultaneously for 13 seconds
- 2
Note the -23 deg C LED lamp blinking to confirm F-DEF error
- 3
Disconnect CN70 wire from MAIN PCB
- 4
Measure resistance between CN70 pin 3 and pin 1
- 5
If 0 ohm: heater is short-circuited - check heater
- 6
If infinite ohm: open circuit - check wire, thermal fuse, or bimetal
- 7
Check F-DEF sensor voltage between CN30 #6 and #8 - should be 4.5V to 0.5V
- 8
Perform forced defrost to verify heater operation
This Error Applies To
Samsung RT Series Refrigerators (2021) (2021–present)
Related Error Codes
Rotary temperature control switch has a fault
Ambient temperature sensor is open or shorted
Freezer defrost sensor evaporator thermistor is open or shorted
Ice maker has a sensor, function, or water pipe heater fault
Refrigerator compartment temperature sensor is open or shorted
Refrigerator compartment fan motor is not spinning or not generating feedback signal
Condenser fan motor is not spinning or not generating feedback signal
Freezer compartment temperature sensor is open or shorted