Error Code F-DEF
Freezer defrost heater or related safety component has failed
Moderate
Address soon - your appliance may not work properly
Also displayed as: F-DEF Error
What This Means
Defrost heater housing connector separated or contact fault; Defrost heater open circuit; Bimetal thermostat stuck open (won't reset at 40°C); Thermal fuse blown (operates at 109-110°C); Excessive ice buildup preventing normal defrost completion
What actually causes this:
The electric heater that melts frost off the evaporator coil has burned out, or a safety fuse in the defrost circuit has blown.
First Thing to Check
Check if the freezer is abnormally frosted over — visible frost buildup from top to bottom of the back wall is a key sign of defrost failure.
Parts Involved
How to Fix
- 1
Disconnect Main PCB CN70 and CN81 wires from PCB
- 2
Measure resistance between CN70 5PIN and CN81 1PIN — should be 63 ohm (230V) ± 7%
- 3
0 ohm indicates heater short circuit
- 4
Infinite (open) resistance indicates wire break or bimetal/thermal fuse open
- 5
Check bimetal thermostat: opens at 140°F (60°C), resets at 104°F (40°C)
- 6
Check thermal fuse: opens at 109°C and does not self-reset
This Error Applies To
Samsung RF59A7670 Series Refrigerators (2022) (2022–present)
Related Error Codes
Interior humidity sensor is faulty or not getting power
The main control board and display panel board have lost communication
Fridge compartment temperature sensor is faulty or disconnected
Machine compartment condenser fan has stopped working
Internal I/O chip on the main board has stopped communicating
External ambient temperature sensor is faulty or disconnected
Main board has lost communication with the Wi-Fi module
Freezer fan motor has stopped working or lost its feedback signal