First make sure the float inside the unit isnt stuck or that nothing is under it holding it up. This will prevent fill because it opens the microswitch so the valve thinks the unit is already full. If the float is free and in the full down position, remove the wire connector from the valve and test the valve solinoid from one terminal to the other to ensure it isnt open. If it shows a resistance that isn't k ohms (or any rediculously high resistance), test for voltage with the door shut to the still disconnected connector. If 120vac is present, replace the water valve. If 120vac is not present, you need to backtrack the circuit to find where the voltage is being dropped (door switch, float switch, wiring, etc.)