Auto defrost issues commonly arise due to problems with the defrost timer, heater, defrost thermostat, defrost thermal fuse, or defrost control board.

When any of these components malfunction, the defrost system may operate for extended periods or fail to activate altogether, both of which are undesirable outcomes.

Prolonged defrosting can harm the refrigerator and impede its cooling capacity, while inadequate defrosting can result in the accumulation of ice and frost, negatively impacting the fridge's efficiency.

Why Do Fridges Have an Auto Defrost Feature?

Refrigerators operate continuously at low temperatures to keep all food items fresh, leading to the accumulation of frost and ice, especially around colder areas such as the evaporator.

These accumulations are undesirable since they occupy space inside the fridge that could be used for additional storage. Furthermore, they can significantly reduce the overall efficiency of your refrigerator.

To address this issue, modern refrigerators are equipped with an automatic defrost system that activates once or twice a day, typically lasting for approximately 25–45 minutes, depending on the brand and model of the refrigerator.

Similar to any other feature in a fridge, the auto-defrost mechanism can experience malfunctions and may require troubleshooting.


Prior to undertaking any repair work on your refrigerator, it is crucial to disconnect the appliance from its power source. This step is essential to eliminate the risk of electrical shock and reduce the overall likelihood of injury. In the case of refrigerators connected to a water line, it is equally important to shut off that line to prevent any potential spills or leaks.

Pros and Cons of Fridge


  • Food Preservation
  • Convenience
  • Food Safety
  • Energy Efficiency


  • Energy Consumption
  • Initial Cost
  • Maintenance
  • Space Requirements
  • Noise

Differences Between Fridge and Dryer


A refrigerator is used for cooling and preserving food and perishable items by maintaining low temperatures. It prevents food from spoiling and extends its shelf life.


A dryer, typically a clothes dryer, is used for drying wet or damp clothing and textiles, such as clothes, towels, and bedding.

Alternative to fridge

Cooler with Ice

For short-term or temporary needs, a high-quality cooler filled with ice packs or ice can keep food and beverages cold. This is useful for outdoor events, picnics, and camping.

Defrost Timer

The defrost timer plays a pivotal role in activating the auto-defrost function at scheduled intervals throughout the day. When the timer initiates the defrost cycle, it supplies power to the defrost heater, maintaining it for a predetermined duration.

The heater's function is to generate sufficient heat to melt any frost or ice accumulation that may have developed around the evaporator coils. Once the defrost cycle concludes, the timer ceases to provide power to the heater, allowing the refrigerator to resume its normal cooling operation.

How It Fails:

If a defrost timer is malfunctioning, it may be unable to progress to the defrost cycle at all. And even if it does, the timer might fail to send power to the defrost heater, resulting in a situation where none of the frost or ice accumulation around the evaporator will thaw or melt away.

How to fix:

While the consequences of a defective defrost timer may not appear significant initially, it is imperative to replace it promptly. The daily defrost cycle is essential for the refrigerator's efficient performance.

Usually, you will find the defrost timer situated in the control housing within the refrigerator.

Here are the steps to replace it:

  1. Begin by removing the control housing. Unscrew and detach any wire harnesses, securing them in place.
  2. Next, take out the old defrost timer along with its electrical connector.
  3. Install the new defrost timer, ensuring you reconnect the connector in the same manner as before.
  4. Finally, reposition the control housing inside the refrigerator and secure it back in place.

This replacement process will help restore the proper functioning of the defrost timer and, in turn, ensure your refrigerator operates efficiently.

Defrost Heater

The defrost heater is a simple component, consisting of a heating element positioned in close proximity to, or around, the evaporator coils. During the auto-defrost cycle, initiated by the defrost timer, power is supplied to the defrost heater, causing it to produce heat.

As a result, any ice or frost buildup around the evaporator will melt, and the water will flow into the refrigerator's drip pan. Over time, this accumulated water in the drip pan will naturally evaporate.

Read Also: What should my frigidaire fridge and freezer be set at?

How It Fails:

Similar to any heating element, the defrost heater is susceptible to potential failure. These failures could result from physical damage, such as if the heater endured a significant impact. Alternatively, an electrical issue may arise where no power can pass through the heater.

In either case, such problems can lead to the heater's failure, causing it to be incapable of generating any heat. Consequently, it will be unable to melt any frost or ice accumulation around the evaporator coil.

How to Fix:

Regrettably, a malfunctioning defrost heater cannot be repaired and should be replaced instead. The defrost heater can typically be found inside the refrigerator, positioned towards the rear. To access the heater, follow these steps:

  1. Remove the back cover and disconnect any wire harnesses attached to it.
  2. Next, unplug the electrical connectors from the defrost heater and detach it. The heater might be secured in place with either mounting screws or aluminium straps.
  3. Take out the old defrost heater and replace it with the new one.
  4. Secure the new heater in place and reconnect its electrical connector in the same manner as the old one.
  5. Lastly, reinstall the back cover and reattach the wire harnesses that were removed at the beginning of the process.

Defrost Thermostat

The defrost thermostat serves a distinct purpose by continuously monitoring the temperature of the evaporator coils. When it detects that the coils have become excessively cold, the thermostat will enable power to reach the defrost heater. Subsequently, the heater will initiate the melting process, eliminating any frost or ice that may have accumulated around those coils.

How It Fails:

A malfunctioning defrost thermostat will be unable to accurately detect the temperature around the evaporator coils. Consequently, even when the coils become excessively cold and ice and frost accumulate around them, the thermostat will fail to activate the heater by allowing power to flow to it. This can result in a failure to melt the ice and frost as needed.

How to Fix:

To resolve this issue, you'll need to replace the defrost thermostat, which is typically located behind the rear panel inside the fridge. Here's how to do it:

  1. Locate the defrost thermostat, which is usually attached to the refrigerant tubing near the evaporator coils.
  2. Carefully cut the wires connected to the thermostat as close as possible to their point of connection with the thermostat.
  3. Take the new defrost thermostat and connect the wires. You can effectively secure the connections with wire nuts and seal the connection with silicone sealant.
  4. Finally, reattach the new thermostat in the same location where you removed the old one.

Following these steps will enable you to replace the defrost thermostat and ensure the proper functioning of the auto-defrost system.


The auto-defrost system is a crucial component in modern refrigerators, as it helps prevent frost and ice buildup around the evaporator coils, ensuring efficient cooling and storage space. When key components such as the defrost timer, defrost heater, or defrost thermostat malfunction, it can lead to issues with the system's operation.

Addressing these issues often involves replacing the faulty component, as repair may not be feasible. It's important to follow proper safety procedures and steps to diagnose and replace these components, ultimately restoring the refrigerator's functionality and efficiency. Regular maintenance and prompt troubleshooting are essential to keeping your refrigerator in good working condition.

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