The defrost heater is responsible for melting frost that may accumulate on the evaporator coils. If it fails, frost can build up, impairing the refrigerator’s ability to cool properly. Here’s a step-by-step guide to test the defrost heater.
Caution: Please read our safety information before attempting any testing or repairs.
Important Safety Notice: Before testing the defrost heater, unplug the refrigerator to avoid an electrical shock hazard.
Tools and Materials Needed
- Screwdriver (Phillips and flat-head)
- Needle-nose pliers
- Multimeter
- Safety gloves
Steps to Test the Defrost Heater
Step 1: Safety First
- Turn Off Power: Unplug the refrigerator to prevent any electrical shock.
- Wear Safety Gear: Wear safety gloves to protect your hands while working.
Step 2: Access the Defrost Heater
- Locate the Heater: The defrost heater is usually located at the back of a side-by-side freezer or under the floor of a top freezer.
- Remove Obstructions: Empty the freezer, and remove the freezer shelves and icemaker if necessary.
- Remove the Access Panel: The panel covering the heater may be held in place by retainer clips or screws. Use a screwdriver to remove the screws or depress the retainer clips with a small screwdriver.
Step 3: Identify the Heater Type
- Types of Heaters: There are three primary types of defrost heater elements:
- Exposed metal rod
- Metal rod covered with aluminum tape
- Wire coil inside a glass tube
Step 4: Disconnect the Heater
- Locate the Wires: The heater is connected by two wires with slip-on connectors.
- Remove the Connectors: Firmly pull the connectors off the terminals using needle-nose pliers if necessary. Do not pull on the wires themselves.
- Inspect for Corrosion: Check the connectors and terminals for corrosion. Replace the connectors if they are corroded.
Step 5: Test the Heater with a Multimeter
- Set the Multimeter: Set your multimeter to the ohms setting (Ω) on the X1 scale.
- Test for Continuity: Place one probe on each terminal of the heater. The multimeter should display a reading somewhere between zero and infinity.
- Normal Reading: A reading between zero and infinity indicates continuity.
- Zero or Infinity Reading: If the reading is zero or infinity, the heating element is bad and should be replaced.
Step 6: Interpret the Results
- Check Schematic for Ratings: If available, refer to the refrigerator’s schematic to determine the correct resistance rating of the defrost heater.
- Inspect the Element: The element may have the resistance rating labeled on it.
Step 7: Reassemble the Freezer
- Reconnect the Wires: If the heater is functional, reconnect the wires to the terminals.
- Replace the Access Panel: Secure the access panel with screws or clips.
- Reinstall Freezer Components: Replace the shelves and icemaker, and return the contents to the freezer.
Step 8: Restore Power and Test
- Plug in the Refrigerator: Restore power by plugging the refrigerator back in.
- Test the Refrigerator: Observe the refrigerator to ensure it is cooling properly and that frost is not accumulating.
Tips and Warnings
- Use Proper Tools: Ensure you use the correct tools to avoid damaging components.
- Handle with Care: When handling glass tube elements, be gentle to avoid breakage.
- Consult the Manual: Always refer to your refrigerator’s user manual for specific instructions related to your model.
- Seek Professional Help: If you are unsure about any step or if the problem persists, consider seeking help from a professional technician.
By following these steps, you can effectively test the defrost heater in your refrigerator, ensuring it operates correctly and efficiently. Regular maintenance and timely repairs will help extend the lifespan of your appliance.
