Symptoms
- Frost building up despite being labeled frost-free
- Airflow reduced or blocked over time
- Compartment gradually warms as frost builds
- Cycle used to work fine before
Likely causes
- CommonFailed defrost heaterThe heating element that melts frost periodically can burn out over years of use.
- CommonFaulty defrost thermostatThis component senses when the coil is cold enough to need defrosting and can fail closed or open.
- PossibleBroken defrost timer or control boardThe component that schedules defrost cycles can fail, stopping the process entirely.
- PossibleDefrost drain clogged, freezing water back onto the coilEven with a working heater, a clogged drain can let melted frost refreeze in place.
What to do
- Unplug the unit and manually defrost it fully by leaving the door open with towels underneath for several hours.
- Once defrosted, plug it back in and monitor over the next week to see if frost returns.
- If frost returns within days, the defrost heater or thermostat has likely failed and needs testing.
- Check the defrost drain (usually a small hole at the back of the freezer) for clogs and clear gently with warm water if accessible.
- Avoid repeatedly manual-defrosting as a permanent fix, since the underlying component will keep failing.
- Have a technician test the defrost heater, thermostat, and timer as a set, since they work together.
Tools and parts
- Towels
- Warm water
Defrost heater assemblySearch: “refrigerator defrost heater kit”
Defrost timerSearch: “refrigerator defrost timer”
When to call a pro
If frost keeps returning after a manual defrost, have a technician test and replace the defrost heater, thermostat, or timer as needed.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.