How do I fix error code F-DEF-ERROR on a Samsung refrigerators?

1. undefined: Activate forced defrost via test mode (Fridge + Power Cool 6 seconds, then press Lock/Freezer key) 2. undefined: If defrost heater does not heat, disconnect CN20 and measure resistance between pin 6 and pin 8 3. undefined: Expected: 63 Ω ±7% at 120V or 230 Ω ±7% at 230V 4. undefined: 0 Ω = heater or circuit shorted; ∞ Ω = open heater, bimetal tripped, or thermal fuse blown 5. undefined: Check heater directly at CN70 pin 5 (BRN) to CN85 pin 3 (BLK) — expected 63 Ω ±7% 6. undefined: Visually inspect bimetal thermoprotector and thermal fuse for continuity

Samsung Refrigerators2020–present

Error Code F-DEF-ERROR

Q: What does error code F-DEF-ERROR mean on a Samsung refrigerators?

Freezer defrost heater is burned out or circuit is open Burned-out defrost heater element; Open bimetal thermoprotector (trips at 140°F/60°C, resets at 104°F/40°C); Blown thermal fuse (F-thermos fuse: rated AC 250V 15A, cuts at 109–110°C); Broken wiring between Main PCB and defrost heater assembly; Failed PCB relay controlling defrost circuit

Freezer defrost heater is burned out or circuit is open

Moderate

Address soon - your appliance may not work properly

Also displayed as: F blinks (freezer defrost error — CN20 item 24 in self-diagnosis list)

What This Means

Burned-out defrost heater element; Open bimetal thermoprotector (trips at 140°F/60°C, resets at 104°F/40°C); Blown thermal fuse (F-thermos fuse: rated AC 250V 15A, cuts at 109–110°C); Broken wiring between Main PCB and defrost heater assembly; Failed PCB relay controlling defrost circuit

What actually causes this:

The heating element that melts frost off the freezer coils has failed — frost will build up on the evaporator causing the fridge to stop cooling.

First Thing to Check

Look in the freezer for unusual frost buildup on the back wall behind the evaporator cover — this is a sign that defrost has stopped working.

Parts Involved

Defrost heater (AC 120V, 230W)Bimetal thermoprotector (AC 125V 6A, off at 140°F/60°C)Thermal fuse (AC 250V 15A, cuts at 110°C)Main PCBCN20 connector

How to Fix

1
Activate forced defrost via test mode (Fridge + Power Cool 6 seconds, then press Lock/Freezer key)
2
If defrost heater does not heat, disconnect CN20 and measure resistance between pin 6 and pin 8
3
Expected: 63 Ω ±7% at 120V or 230 Ω ±7% at 230V
4
0 Ω = heater or circuit shorted; ∞ Ω = open heater, bimetal tripped, or thermal fuse blown
5
Check heater directly at CN70 pin 5 (BRN) to CN85 pin 3 (BLK) — expected 63 Ω ±7%
6
Visually inspect bimetal thermoprotector and thermal fuse for continuity

This Error Applies To

Samsung RF28T5 Series Refrigerators (2020) (2020–present)

Service manual exact match: RF28T5101SR/AAService manual exact match: RF28T5A01S9/APService manual exact match: RF28T5021S9/EMService manual exact match: RF28T5001S9/MLService manual exact match: RF28T5021B1/COService manual exact match: RF28T5A01SR/AAService manual exact match: RF28T5021SR/AAService manual exact match: RF28T5001SR/AA