How to Test the Defrost Heater on Your LG Refrigerator

Written By: Bill Gilbert

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How to Test the Defrost Heater on Your LG Refrigerator

Difficulty

Moderate

Steps

Time Required

1 - 2 hours

Introduction

Use this guide to test the defrost heater on your LG refrigerator.

This guide will work for most LG refrigerators. This guide is written with an LG model LFX25973 refrigerator. If you have a different model, you may encounter some minor disassembly differences, but the overall repair process will be the same.

The defrost heater provides the heat needed to melt the accumulated ice on the evaporator coils to allow the refrigerator to function correctly.

If it fails, the defrost cycle will not work, and the fridge will start to work poorly, usually running warm in the fresh food (refrigerated) section.

You will need to use a multimeter for the resistance test.

Tools

Step 1

Unplug your refrigerator before you begin your repair.
If you are testing or repairing the following items, you may also need to shut off and disconnect the water supply:
Condenser fan motor
Compressor motor and thermal overload device
Water supply valve assembly

Step 2

Pull open the freezer door fully.

Step 3

Lift and remove the upper pull-out drawer.
Lift and remove the main drawer bin.

Step 4

Use your finger or a flat-blade screwdriver to depress the two locking tabs on the right drawer rail cover.
Lift the cover off of the rail and remove it.
Repeat this procedure for the left drawer rail cover.

Step 5

The drawer rail covers can be tricky to reinstall. Follow these steps to reinstall them:
Hold the drawer rail cover flush against the side of the drawer rail.
You should feel the locking tabs protruding.
Push the rail cover straight downward to install. It should click into place.

Step 6

Use a Phillips screwdriver to remove the screw securing the drawer to each of the drawer slides.

Step 7

Lift the front of the drawer up.
Pull the drawer toward you to release the drawer from the drawer slides.
Remove the freezer drawer.

Step 8

Use a Phillips screwdriver to remove the screws securing both left drawer slides.

Step 9

Pull the upper left drawer slide slightly towards you to release the locking tab at the rear.
Remove the upper left drawer slide.

Step 10

Pull the lower left drawer slide slightly toward you to release the locking tab at the rear.
Reposition the lower left drawer slide to gain access to the door switch connector.

Step 11

Squeeze the door switch connector to release it.
Pull the door switch connector down to disconnect it.
Remove the lower left drawer slide.
If you are removing the freezer evaporator cover, likely only the left-hand slides may need to be removed. In some cases you will need to repeat the previous three steps to remove the right slides as well.

Step 12

Use a Phillips screwdriver to remove the screws securing the ice maker to the top of the freezer compartment.

Step 13

Insert a flat-blade screwdriver into the slot located on the right edge of the ice maker.
Pry outward with the screwdriver to release the locking tab securing the ice maker to the fridge.
When the tab releases, pull the right front corner of the ice maker down.

Step 14

Repeat the previous operation on the left side of the ice maker to release it.

Step 15

Grasp the front edge of the ice maker and pull it towards you.
Lower the ice maker.

Step 16

Squeeze the ice maker connector to release it and pull it straight out to disconnect it.
Remove the ice maker.

Step 17

Pinch the rear portion of the air return cover to release it from the freezer wall.
Pull the air return cover outward and remove it.

Step 18

Use a Philips screwdriver to remove the screw (or screws) securing the evaporator cover.

Step 19

Don't try to remove the evaporator cover fully, as It is still connected to the fridge with a number of wires.
Grasp the evaporator cover by the air vent openings and pull the top edge toward you.

Step 20

Lift the evaporator cover slightly to release the tabs at the lower edge.
Swing the left edge of the evaporator cover toward you and lower it.

Step 21

Disconnect the electrical connections in the upper left corner of the freezer.
Make a note of the locations of the connections for re-installation.

Step 22

Swing the left edge of the evaporator cover further toward you to access the connections in the upper right corner.
Squeeze and pull the connector to disconnect the thermistor mounted in the evaporator cover.

Step 23

Remove the evaporator cover.

Step 24

If you have a multimeter, you can test the defrost heater for proper resistance.
Set the multimeter to the ohm setting.
Trace the two wires of the defrost heater to its connector. Disconnect the connector by squeezing the tab and pulling it straight out.
In this case, the defrost fuse and the heater are wired in series, so your test will also show if the fuse is ok.
In the photos here, the orange wires are for the defrost thermistor, not the defrost heater. The heater wires will usually be larger sized.