How can you verify the proper function of a refrigerator's defrost timer?

To verify the proper function of a refrigerator's defrost timer, observing if it cycles correctly and checking continuity across its terminals is essential. The defrost timer controls the operation of the defrost heater in the refrigerator, ensuring that it periodically removes frost buildup from the evaporator coils.

By monitoring the cycling of the defrost timer, you can ensure it transitions from cooling mode to defrost mode as designed. If the timer is functioning correctly, you will observe a switch from the compressor running to the activation of the heating elements during the defrost cycle. Checking continuity across its terminals allows for confirmation that electrical current flows when expected, indicating that the component is functioning properly.

Other methods such as checking the temperature inside the refrigerator can provide information on overall performance but do not specifically assess the timer's function. Listening for unusual noises might indicate other issues, but it does not directly verify the timer's operation. Inspecting the external condition of the timer can give some insight into its physical state, but does not ensure that the internal mechanisms are working as intended. Thus, observing the cycling and checking continuity are the most direct measures of ensuring the defrost timer operates as required.