How to test refrigerator defrost heater

How to test refrigerator defrost heater


The defrost heater in a refrigerator is an essential component that helps prevent the buildup of frost and ice on the evaporator coils. It plays a crucial role in maintaining optimal cooling efficiency by periodically melting any ice or frost that forms on the coils.

Defrost heater in a refrigerator

The defrost heater in a refrigerator is an essential component that helps prevent the buildup of frost and ice on the evaporator coils. It operates during the defrost cycle, melting any accumulated ice or frost to maintain optimal cooling efficiency. Here are some key points to understand about refrigerator defrost heaters:


The defrost heater's primary function is to generate heat and raise the temperature of the evaporator coils in the freezer compartment. By doing so, it melts any ice or frost that has formed on the coils, allowing proper airflow and preventing blockages that can hinder cooling performance.


The defrost heater is typically located behind the rear panel of the freezer compartment, adjacent to or wrapped around the evaporator coils. In some refrigerator models, it may also be located underneath the refrigerator, near the drain pan area.


There are two common types of defrost heaters found in refrigerators:

Electric Resistance Heater: This type of defrost heater consists of a resistive heating element, usually made of metal alloy, such as nichrome wire. When an electric current passes through the heater, it generates heat, which is transferred to the evaporator coils.

Defrost Heater with a Glass Tube and Coil: In some newer refrigerators, a glass tube with a conductive coating and a coiled wire inside is used as the defrost heater. When an electric current flows through the wire, it heats up, and the heat is transferred to the glass tube, which then warms the evaporator coils.



As mentioned in the previous response, testing the defrost heater typically involves measuring its resistance with a multimeter. The specific resistance value can vary depending on the refrigerator model and heater specifications. Consult the manufacturer's documentation or technical specifications for the expected resistance range. A resistance reading falling outside the specified range or no continuity indicates a faulty defrost heater that may require replacement.


If you determine that the defrost heater is faulty or not functioning correctly, it's essential to replace it with a compatible heater designed for your specific refrigerator model. Replacement procedures can vary, so consult the manufacturer's instructions or seek professional assistance to ensure proper installation and avoid any potential damage to the refrigerator.


Remember, working with electrical components can be dangerous, and it's important to prioritize safety. If you are uncertain about testing or replacing the defrost heater, it's best to consult a qualified technician or contact the manufacturer for guidance and assistance.

 A Step-by-Step Guide to Testing Your Refrigerator's Defrost Heater

If you suspect an issue with your refrigerator's defrost heater, testing it can help identify the problem.In this blog post, we'll walk you through a step-by-step guide on how to test your refrigerator's defrost heater to ensure it's functioning correctly.

Step 1: Safety First

Before starting any testing procedures, prioritize your safety by unplugging the refrigerator from the power source. This precaution is crucial to avoid electric shock and ensure a safe testing environment.

Step 2: Access the Defrost Heater

Locate the defrost heater, which is typically found behind the rear panel of the freezer compartment. Depending on your refrigerator model, you may need to remove screws, clips, or panels to access the heater. Consult your refrigerator's user manual or manufacturer's instructions for specific guidance.

Step 3: Inspect the Heater

Carefully examine the defrost heater for any visible signs of damage, such as burnt or broken wires. If you notice any obvious issues, such as physical disintegration or visible damage, it's likely that the heater needs to be replaced. However, if there are no visible signs of damage, proceed to the next step.

Step 4: Disconnect the Heater

The defrost heater is typically connected to the refrigerator's wiring harness with connectors or wire terminals. Gently disconnect the wires or terminals that connect the heater to the electrical system. Take note of their positions to ensure proper reconnection later.

Step 5: Testing for Continuity

To determine if the defrost heater is functioning correctly, you can use a multimeter set to measure resistance (ohms) and test for continuity.

Step 6: Set up the Multimeter

Set your multimeter to the resistance or continuity mode. Ensure the multimeter is functioning properly and the test leads are connected securely.

Step 7: Test for Continuity

Place one test lead of the multimeter on one terminal of the defrost heater and the other lead on the other terminal. The multimeter should indicate continuity if the heater is functioning correctly. If there is no continuity, it suggests a problem with the heater.

Step 8: Compare Resistance Values

If your multimeter measures resistance instead of continuity, you can compare the resistance reading to the expected range specified in your refrigerator's user manual or technical documentation. If the measured resistance falls within the specified range, the defrost heater is likely functioning correctly. However, if the resistance reading is significantly higher or lower than the expected range, it indicates a faulty defrost heater that requires replacement.

Step 9: Reconnect and Reassemble

If the defrost heater passes the continuity or resistance test and appears to be functioning properly, reconnect the wires or terminals to the heater, ensuring they are securely fastened. Carefully reassemble the refrigerator's rear panel or any components that were removed to access the heater.

Step 10: Monitor the Defrost Cycle

Once you have completed the testing and reassembly, plug the refrigerator back into the power source. Monitor the defrost cycle over a period of time to see if the heater is activating as it should. If the defrosting problem persists or the heater is still not functioning correctly, it may be necessary to consult a professional technician for further assistance.


Testing your refrigerator's defrost heater is an important step in diagnosing issues with frost and ice buildup. By following this step-by-step guide, you can determine if the defrost heater is functioning correctly. Remember, if you're uncertain about any aspect of testing the defrost heater or you're not confident in your abilities, it's always best

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