This DIY repair guide gives step-by-step instructions for replacing the overfill float switch. The overfill float switch trips to shut the water fill valve if the water level gets too high. If the switch fails, it either won't shut off the water, or it won't let the dishwasher fill at all. In either case, you can correct the problem by replacing the float switch with a manufacturer-approved dishwasher part.
These instructions are for Kenmore, Whirlpool, KitchenAid, Maytag, JennAir and Amana dishwashers. You also can use the same basic procedure to replace the overfill float switch in some GE, Frigidaire, Electrolux and Samsung models.
A broken overfill float switch is just one of a few reasons a dishwasher won't fill with water. To pinpoint why a dishwasher won't fill, see the Dishwasher Not Filling troubleshooting video.