Error Code F_DEF_ERROR
Freezer defrost heating cycle not functioning properly
Critical
Stop using immediately - risk of damage or safety issue
Also displayed as: F DEF ERROR
What This Means
Defrost heater open circuit (infinity resistance, typically 63 ohms nominal); Defrost heater short circuit (0 ohms); Bimetal thermostat failure or disconnection; Bad connector contact at CN70 or CN85; Wiring disconnection or corrosion; Defrost relay failure on MAIN PCB
What actually causes this:
The defrost heater failed or disconnected, so ice buildup cannot be melted from the evaporator
First Thing to Check
Manually trigger defrost mode and check if heater gets warm; measure heater resistance
Parts Involved
How to Fix
- 1
Manually trigger defrost using test mode (Fridge + Power Cool keys for 6 seconds)
- 2
Check defrost sensor temperature below 53.6F (12C) before heating
- 3
Measure heater resistance between CN70 pin 5 (BRN) and CN85 pin 3 (BLK): should be 63 ohms ±7%
- 4
Measure defrost sensor resistance between CN20 pins 6 and 8
- 5
Verify heater power signal during defrost cycle
- 6
Check defrost cycle completion (return to cooling after heating)
Other Error Codes for RF28T5021B1
Refrigerator compartment temperature sensor is disconnected or dead
Internal humidity sensor has failed or is disconnected
Defrost sensor on freezer evaporator is failed or disconnected
Freezer fan motor is not running or not sending feedback
Supply voltage to compressor is too high
Freezer temperature sensor is failing or disconnected
Ice maker temperature sensor in freezer is failed or unplugged
External room temperature sensor is failed or disconnected