February 20, 2015

How to replace a freezer defrost thermostat

By Lyle Weischwill
How to replace a freezer defrost thermostat

This DIY repair guide explains how to replace the defrost thermostat in an upright freezer. The defrost thermostat, also called a bi-metal, protects the evaporator by turning the defrost heater off if the heater gets too hot. If the defrost thermostat stops working, frost forms on the evaporator fins, and the temperature in the freezer rises. Replace the defrost thermostat with the manufacturer-approved replacement part if it's no longer working.

Use these basic steps to replace the defrost thermostat in Kenmore, Frigidaire, Electrolux, GE, Whirlpool, Gibson, Crosley, KitchenAid, Tappan and Amana freezers.

Quick links
Tools required
Phillips screwdriver
Work gloves
Repair difficulty
Time required
45 minutes or less
Repair difficulty
Time required
45 minutes or less
How to replace a freezer defrost bi-metal thermostat video.

Replacing a freezer defrost bi-metal thermostat video.

Instructions

  1. 01.

    Disconnect the electrical power

    Unplug the freezer or shut off the circuit breaker for the freezer.

  2. 02.

    Remove the evaporator cover

    Remove the drawers and shelves from the freezer.

    Remove the screws from the evaporator cover at the back of the freezer.

    Pull the evaporator cover out of the freezer.

    Remove the freezer drawers.

    Remove the freezer drawers.

    Remove the evaporator cover screws.

    Remove the evaporator cover screws.

    Pull out the evaporator cover.

    Pull out the evaporator cover.

  3. 03.

    Remove the defrost bi-metal thermostat

    Unplug the defrost bi-metal thermostat wires.

    Unclip the defrost bi-metal thermostat and remove it.

    Tip: The aluminum fins of the evaporator are sharp. Wear work gloves to protect your hands.
    Unplug the wires.

    Unplug the wires.

    Remove the thermostat.

    Remove the thermostat.

  4. 04.

    Install the new defrost bi-metal thermostat

    Clip the new defrost bi-metal thermostat onto the evaporator.

    Connect the defrost bi-metal thermostat wires.

  5. 05.

    Reinstall the evaporator cover

    Position the evaporator cover on the back wall and reinstall the mounting screws.

    Reinstall the evaporator cover gasket.

    Reinstall the drawers and shelves inside the freezer cabinet.

    Reisntall the evaporator cover.

    Reisntall the evaporator cover.

    Reinstall the evaporator cover gasket.

    Reinstall the evaporator cover gasket.

  6. 06.

    Restore electrical power

    Plug in the freezer or turn on the house circuit breaker to restore power.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.

Symptoms common to all freestanding freezers

Choose a symptom to see related freezer repairs.

Main causes: lack of power, bad compressor, refrigerant leak, bad thermistor, defrost system failure, dirty condenser coils, control failure
Main causes: leaky door or lid gasket, broken defrost heater, bad defrost bi-metal thermostat, defrost control failure, faulty compressor
Main causes: lack of power, control system failure, broken compressor start relay, locked up compressor, compressor motor failure
Main causes: burned out light bulb, bad door or lid switch, faulty LED light board, wiring failure, control system failure
Main causes: damaged door or lid gasket, cracked cabinet liner, bad defrost bi-metal thermostat, broken defrost heater, bad defrost timer
Main causes: compressor failure, no refrigerant, faulty sensor, control failure, broken defrost heater, bad defrost bi-metal thermostat
Main causes: excessive frost, bad defrost heater, bad defrost bi-metal, control system failure, low refrigerant charge, compressor problems
Main causes: dirty condenser coils, condenser fan failure, dirty bottom front grill, leaky door or lid gasket

Repair guides for upright freezers

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February 20, 2015
By Lyle Weischwill
How to replace a freezer defrost thermostat

These step-by-step instructions explain how to replace the defrost bi-metal thermostat in an upright freezer.

Repair difficulty
Time required
 45 minutes or less

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