When the water in the tub lifts the float to a set point, the float switch is triggered and it shuts off the water inlet valve, stopping the flow of water. If the float switch is defective, the tub may overfill.
Before testing the float switch, unplug the dishwasher or shut off the power at the fuse
box or breaker
panel to avoid an electrical shock hazard.
To access the float switch remove
the lower panel located beneath the door. The panel is usually
held in place with two screws either above or below the panel.
It may be necessary to first open the door to the dishwasher to
reach the screws over the panel, then close the door to remove
the panel.
Note the location of the float in
the dishwasher's tub and you will find the float switch beneath
it in the access area. The switch has two wires connected to it.
Label the wires and connections so that you can properly reconnect
them later. The wires are connected with slip on connectors. Firmly
pull the connectors off of the terminals (do not pull on the wire
itself). You may need to use a pair of needle-nose pliers to remove
the connectors. Inspect the connectors and the terminals for corrosion.
If either is corroded they should be cleaned or replaced.
Use a continuity tester or multitester
to test for continuity.
Set the multitester to the ohms setting X1. Touch one probe to
each terminal. You should get a reading of either zero or infinity.
With the probes still in place, depress the button or lever on
the switch and the reading should change to the opposite extreme.
If the switch fails either test, it should be replaced.
Before testing the float switch, unplug the dishwasher or shut off the power at the 
