I have a Maytag dishwasher that will not drain. everything else is working. The dishwasher is at my parents home. My father recently passed and my mom is in a nursing facility so the washer hasn't been used much over the past year. When i hit the drain button it runs through a wash cycle and when complete ( 2 minutes ) it is still full of water. I have taken the mechanism apart down to the drain impeller but nothing is broken. I see that the wash impeller and the drain impeller are both on the same motor shaft so my question is how does the dishwasher know that it is supoosed to be draining rather than washing. I didn't see any solenoids that might switch between the 2 different cycles but I may be missing something. I really need an electrical schematic if anyone can supply one.

Thanks for the help,
Randy