Whirlpool Defrost Timer (W10189190)

The Whirlpool Defrost Timer controls when the refrigerator switches between cooling mode and defrost mode. It runs the compressor and fans for a set period, then shuts cooling off and sends power to the defrost heater to melt frost from the evaporator. After the timed defrost cycle ends, it restores power to cooling so temperatures can recover. Failure often comes from worn timer gears, a weak or stalled timer motor, or burned internal contacts. These issues can stop the timer from advancing or can leave it stuck in either cooling or defrost. Power surges and normal wear over time can also cause intermittent switching. These symptoms can help you decide if this timer matches your problem: Frost builds up on the back wall of the freezer or on the evaporator coils, and airflow gets weak The refrigerator warms up because it stays in defrost too long or does not return to cooling The unit runs for long stretches with heavy frost, suggesting it is not entering defrost Cooling and defrost seem to switch at random, causing temperature swings Manually advancing the timer changes operation, but it does not advance on its own