Hello,
I would disconnect power from the dishwasher and also shut the water off to it. Then, I would take the water valve off to see if there is sediment build up in the filter screen that would block the water flow to the dishwasher. If that checks out ok, I would test the valve by either testing the coils for continuity or testing for voltage at the valve when you start the dishwasher. If you have voltage at the valve and no water, your valve needs replacing.
Hope this helps.
JP, February 2008