The Ultrafresh fan is controlled by sensors and runs based on an algorithm based on when moisture is detected between cycles. It may be able to be heard as a low hum, depending on your home’s setup. The fan can run with or without dishes in the dishwasher, regardless of if the door is open or closed. -- Pressing the ULTRAFRESH pad will activate the system and will
illuminate the LED just above the ULTRAFRESH pad. The UltraFresh feature may be turned off at any time by pressing the ULTRAFRESH pad a second time. For more information, please see the Ultrafresh section on page 7 of the Owner’s Manual, which can be viewed at the bottom of the Features tab of the Best Buy product page.