The function of the float is to trigger the level switch so it turns off the flow of water to the dishwasher when it reaches the desired level. If the float becomes stuck, it can’t move freely and can keep your dishwasher from filling or draining properly. Before you begin working, unplug your dishwasher. To locate the float assembly, remove the lower dishrack and look on the bottom of the dishwasher’s tub. Test the float by lifting it several times and letting it drop. Remove the float and look for obstructions. Clean any debris you find and replace the float assembly. If you find no debris, or if you dishwasher still isn’t working properly after you clean the float assembly, you’ll need to test the level switch.
To locate the level switch, remove the kickplate panel found below the dishwasher door. The level switch will be on the right side of the sump assembly. It will have several wires and one small rubber hose connected to it. Label the wires so you can reconnect them properly later. To remove the wires, pull firmly on the slip-on connectors. Do not pull directly on the wires.
Use a multimeter to test the level switch for continuity. Set your multimeter to the lowest setting for ohms of resistance and test each of the three possible pairs of terminals by touching one of the probes on the meter to a switch terminal while you touch the other probe to a different terminal. Press down on the switch’s button. Note the reading, then move one of the probes to the other terminal and press the switch’s button again. Repeat with the final pair of terminals. The readings you receive should be either zero or infinity if the switch is good. If you don’t see a change in the reading, you have a bad switch.
If the level switch is working properly, or you’re still having problems after replacing it, you should inspect the water inlet valve and the drain valve and solenoid. Dirty filter screens on the water valve can keep your dishwasher from filling up as can an improperly functioning drain valve. Use a multimeter to test these parts.