Step1: Disconnect power to the refrigerator before servicing electrical components.
Step2: Remove the access panel near the compressor or control section to locate the timer.
Step3: Label and disconnect the wiring from the old defrost timer terminals.
Step4: Remove the mounting screws securing the defective timer assembly.
Step5: Install the new defrost timer in the same position and reconnect wiring correctly.
Step6: Reattach the access panel, restore power, and verify proper cooling and defrost cycling.