The Whirlpool WP3406102 Dryer Switch Door is an essential component for your clothing dryer. It's a safety mechanism and a control component all in one. The switch is located near the door latch and detects the position of the dryer door. When you close the dryer door, the switch is pressed in, indicating to the dryer that it is safe to start the drying cycle. In contrast, opening the door during a cycle deactivates the switch, causing the dryer to halt and prevent hot garments from tumbling out. A broken dryer door switch can cause your dryer to malfunction in a variety of ways, including failure to start or sudden termination.