This symptom of the unit filing and then not washing can be caused by few things.
1. The water level pressure switch not making contact to the motor control circuit but shutting off the water valve. There should be 120 VAC on the yellow wire of the water level control pressure switch when the fill level has reached the correct level.
2. An internal timer contact problem for the motor control circuit. Power for the timer motor should also be present on terminal 14 of the timer.
3. A defective motor speed switch. There should also be power on the yellow wire going to the motor.
All of the above power is sourced via the lid switch.
Black wire is power in. You know you have power in... as it fills.
Schematic:
http://www.appliancepartspros.com/partsearch/frame_diagram.aspx?diagram_id=1330708&pkw_=basket&model_id=5170285&NewWindow=1
This is going to take a meter to isolate the problem. Changing parts can get expensive but treouble shooting with a meter will result in determining where the failure has occurred.
Thanks for using FixYa.
Kelly