Whirlpool · Refrigerator Serious
dF — Defrost System Failure
The control board did not see the evaporator temperature rise during a defrost cycle, meaning the defrost heater, defrost thermostat, or bimetal sensor is not working. Frost will keep building on the coil until airflow is choked and the fridge stops cooling.
- Keep using it?
- Limited use only
- DIY difficulty
- Hard
- Verified against
- ifixit.com ↗
How to fix it
- Manually defrost the fridge — unplug, empty the freezer, leave doors open 8+ hours with towels on the floor.
- Once thawed, remove the freezer back panel to expose the evaporator coil.
- Test the defrost heater for continuity (should read a few dozen ohms).
- Test the bimetal/defrost thermostat by chilling it in ice water and ohming — should close cold.
- Replace the failed component. If both test good, replace the main control board.
Why it happens
Typical signs: 'dF' on display · Heavy frost on freezer back panel · Fresh food warming up while freezer stays cold · Fan noise from blocked evaporator
- Failed defrost heater Heater coil has gone open and is not melting frost.
- Failed defrost thermostat / bimetal Bimetal stuck open and never closes to power the heater.
- Damaged defrost element wiring Burned wire or terminal at the heater.
- Failed main control board Defrost relay on the board failed.
Parts you may need
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
More Whirlpool refrigerator codes
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: ifixit.com.