Few things are as stressful as finding a puddle of melted ice cream in a freezer that’s not freezing. Today, most freezer failures are related to heat exchange efficiency rather than a “dead” machine. This guide ranks the most common causes from most likely to least likely to help you save your groceries and your budget.
5 Common Causes for a Freezer Not Freezing
1Dirty Condenser Coils
Condenser coils dissipate heat from inside the unit into your kitchen. If they are coated in dust, pet hair, or kitchen grease, the heat stays trapped, and the freezer won’t be able to reach 0°F.
Symptoms
- The compressor runs constantly but the freezer stays at “refrigerator” temperatures.
- The sides or back of the unit feel excessively hot.
Care Plan
- Unplug the unit and locate the coils (usually behind a bottom grate or on the back).
- Use a vacuum with a crevice tool or a specialized coil brush to remove debris.
- If the coils are oily, use a damp cloth with mild detergent to wipe them clean.
- Ensure there is at least 2 inches of clearance between the unit and the wall.
- Restore power and wait 24 hours for the temperature to stabilize.
Common Mistakes
- Cleaning only the front of the coils and ignoring the dust trapped deep in the back.
2Failed Evaporator Fan Motor
The evaporator fan pulls air across the cold coils and circulates it throughout the freezer. If the motor fails or the blades are obstructed, the coils will get cold, but the air in the freezer will stay warm.
Symptoms
- You can hear the compressor (humming) but you don’t hear the whir of the fan.
- The back wall of the freezer feels icy, but the front is warm.
Care Plan
- Open the freezer and listen for the fan; it should stop when you open the door and start when you press the door switch.
- If silent, remove the back panel inside the freezer.
- Check if ice has built up and frozen the fan blades in place.
- If the blades spin freely but the motor is silent or growling, check for voltage at the fan terminals (typically 120V AC on most models, or DC on some inverter units).
- Replace the fan motor if it receives power but fails to turn.
Common Mistakes
- Replacing the motor when it was simply jammed by a rogue ice cube or a frost buildup.
3Frosted Evaporator Coils (Defrost Failure)
Your freezer has a defrost heater that melts ice off the cooling coils. If the heater, thermostat, or timer fails, the coils will become completely encased in a block of ice, which acts as an insulator and blocks airflow.
Symptoms
- Heavy frost buildup on the back wall of the freezer.
- The unit was working fine but gradually lost cooling power over 2–3 days.
Care Plan
- Manually defrost the unit by unplugging it and leaving the doors open for 24 hours.
- Once clear, test the defrost heater for continuity with a multimeter.
- Test the defrost thermostat; it should have continuity only when it is cold (below 40°F).
- If the components are fine, the defrost control board/timer is likely the culprit.
- Clear the defrost drain tube to ensure melted water isn’t refreezing in the bottom.
Common Mistakes
- Using a hair dryer or ice pick to speed up defrosting; this can melt plastic liners or puncture refrigerant lines.
4Worn Door Gasket (Seal)
If the rubber gasket around the door is torn or has lost its magnetic pull, warm, humid air from your kitchen will leak inside. This creates massive frost buildup and forces the freezer to work overtime.
Symptoms
- You can see visible gaps in the seal.
- Heavy frost forms near the door edges.
- The door opens too easily with almost no resistance.
Care Plan
- Clean the gasket with warm, soapy water to remove sticky spills that prevent a seal.
- Use the “dollar bill test”: Close the door on a bill; if it pulls out with no resistance, the seal is weak.
- Use a hair dryer on a low setting to gently heat and reshape any flattened areas of the rubber.
- Apply a thin layer of petroleum jelly to the hinge side of the gasket to help it slide and seal.
- If the rubber is cracked or brittle, replace the entire gasket.
Common Mistakes
- Replacing the gasket when the freezer was just unlevel, causing the door to hang crooked.
5Faulty Start Relay or Compressor
The start relay is a small device plugged into the side of the compressor. It provides the high-voltage jolt to get the compressor running. If the relay fails, the compressor will never start, or it will try to start and click off immediately.
Symptoms
- You hear a periodic click sound every few minutes, but the compressor never hums.
- The unit is completely silent despite being plugged in.
Care Plan
- Unplug the unit and move it away from the wall.
- Remove the small cover on the side of the compressor.
- Pull the start relay off the compressor terminals and shake it gently; if it rattles excessively (like loose parts inside), the relay is likely failed.
- Replace the relay with an exact OEM part.
- If a new relay doesn’t fix it, the compressor itself may be locked or have an internal electrical short.
Common Mistakes
- Replacing the expensive compressor when the $20 start relay was the only problem.
