Finding your freezer not working but fridge is cold can be baffling. Since most refrigerators use a single compressor to cool both compartments, a “half-working” unit usually points to a failure in how that cold air is moved or regulated. This guide ranks the 5 most likely causes to help you restore the deep freeze.
5 Common Causes for a Warm Freezer with a Cold Fridge
1Frosted Evaporator Coils (Defrost Failure)
If your defrost system (heater, timer, or thermostat) fails, the cooling coils will become encased in a thick block of ice. This is the leading reason why a freezer stops freezing while the fridge remains cool; the ice blocks all airflow from reaching the food in the freezer.
Symptoms
- You see heavy frost or a sheet of ice on the back wall of the freezer.
- The unit gradually lost its “freeze” over several days.
Care Plan
- Unplug the unit and leave the doors open for 24 hours to melt all internal ice.
- Once the back panel is clear, test the defrost heater and defrost thermostat for continuity with a multimeter.
- Check the defrost drain for clogs; standing water can refreeze and block airflow.
- If the heater and thermostat are fine, the defrost control board or timer is likely the culprit and should be replaced.
Common Mistakes
- Using a heat gun or sharp object to remove ice; this can melt the plastic liner or puncture a refrigerant gas line.
2Failed Evaporator Fan Motor
The evaporator fan pulls air across the cold coils and circulates it throughout the freezer. If this motor fails, the fridge may stay cool via passive air sink or a separate damper, but the freezer will quickly rise to room temperature.
Symptoms
- The fridge is at a perfect 37°F, but the freezer is at 30°F or higher.
- You don’t hear the usual whirring sound from the back of the freezer interior.
Care Plan
- Open the freezer and listen for the fan; it should run when the doors are closed.
- Access the fan terminals and check for voltage (typically 120V AC on most models, but many modern/inverter units use DC 12–24V).
- If the fan receives power but doesn’t spin, replace the motor.
- If the fan is silent and has no power, the door switch or control board may be faulty.
Common Mistakes
- Assuming the whole refrigerator is dead when only a $60 motor needs replacing.
3Obstructed Airflow (Overpacking)
In many modern units, the return air vents are small and easily blocked. If you pack too many frozen bags against the back or bottom vents, the air cannot circulate, causing “warm spots” that prevent food from staying frozen.
Symptoms
- The freezer is packed to the brim.
- Some items are frozen solid while others (usually in the front) are soft.
Care Plan
- Ensure there is at least a 1-inch gap between your food and the back wall.
- Check the floor of the freezer for stray ice or food debris blocking the return vents.
- Aim for 70–80% fullness for maximum thermal mass without blocking airflow.
Common Mistakes
- Overstuffing the freezer to “save energy,” which actually forces the motor to run longer and warmer.
4Faulty Freezer Temperature Sensor (Thermistor)
The thermistor is a sensor that tells the control board exactly how cold the freezer is. If it sends the wrong data (e.g., telling the board it is 0°F when it is actually 25°F), the system won’t trigger the cooling cycle specifically for the freezer.
Symptoms
- The freezer temperature is inconsistent.
- The control panel shows a “correct” temperature that doesn’t match a manual thermometer reading.
Care Plan
- Locate the thermistor (usually a small plastic bulb clipped to the side or back interior).
- Test the resistance of the thermistor with a multimeter; the ohms should change as the temperature changes.
- If the resistance is “open” or does not shift according to temperature charts, replace the sensor.
Common Mistakes
- Trusting the digital display on the door over an actual thermometer placed inside the compartment.
5Stuck or Faulty Air Damper
The air damper is a small motorized door that opens and closes to balance air between the two compartments. While it usually regulates air going to the fridge, a failure here can disrupt the overall pressure and airflow balance of the unit.
Symptoms
- One compartment is freezing while the other is warm.
- You hear a clicking or clacking sound coming from the back of the unit where the compartments meet.
Care Plan
- Locate the damper (usually at the back where the fridge and freezer connect).
- Check if the door is physically stuck due to ice buildup or a rogue piece of plastic wrap.
- If the motor is clicking but not moving the door, replace the damper assembly.
Common Mistakes
- Forgetting to check if a simple piece of packaging has been sucked into the damper, holding it open or shut.
