The Whirlpool WP3957750 Dryer Timer Knob is an important component for controlling the drying cycle of your compatible Whirlpool dryer. This white knob serves as the link between you and the dryer's timer. By moving the knob, you can choose a pre-set drying time based on the sort of load you've placed in the machine. The knob sends this option to the dryer's internal timer, which subsequently controls the heating element and drum rotation for the specified time. This allows you to get the right level of dryness for your garments while avoiding over- or under-drying. A defective timer knob can cause malfunctions such as the dryer not starting, running constantly, or turning off early.