Rinse only light stays on. Sometimes when I push other buttons nothing at all happens. Sometimes when I push Wash Cycle and start dishwasher starts and then rinse cycle only light comes back on and dishwasher only rinses. After a while all lights will go off and dishwasher will work properly. But, when it completely finishes washing Rinse Only light comes back on. I assume it is either the Control Panel or the Circuit Board. Any way to determine which one?