The "light" cycle button keeps blinking on this dishwasher. If you press and hold the Cancel button, the "heavy" and "normal" cycle buttons' lights come on and go solid, and the "light" cycle button cuts off, but if you press any other button the "light" cycle goes back to blinking. Sometimes if we leave it for days at a time it goes back to normal, but it is occurring with more frequency and is impeding our ability to use the machine. When the light is blinking like that we can't do anything. Any advice would be much appreciated. Thanks.