If your dishwasher runs but doesn’t fill, either something is wrong with its water supply system or it is draining water too soon.

1) First make sure the water is turned on. Check the hot water supply stop valve, normally located under the sink. Open it all the way by turning it counterclockwise. If there is no reason this would have been turned off since the last time the dishwasher worked, go on to the next step.

2) Turn off the power to the dishwasher.

3) When the dishwasher is cool, look for the float inside the dishwasher; this is usually a small plastic dome or cylinder mounted inside at the tub’s base, near the front. When you move most types of floats up and down, you can hear them click because they trip a lever (they are spring-loaded). Lift out the float mechanism, and clean around the float tube. Many floats must be disconnected from below; to do this you’ll have to remove the lower access panel. Rinse off the float, replace it in the tube, and make sure it moves up and down freely.

4) If you’re experienced with minor repair work, shut off the hot water valve to the appliance. Locate the water intake valve, behind the dishwasher’s bottom front panel. Disassemble the valve to reveal the screen, clean debris from the screen, and reassemble. If the screen doesn’t appear to be blocked, call a repairperson (who will probably need to replace the water intake valve).

5) If none of this helps, call a repairperson. Any of several parts—including the water inlet valve, pressure switch, and the timer or selector switch—may be faulty.