My dishwasher fills, but won't start running. it just sits full of water and just hums.
Ok so your dishwasher won't do anything... it justs sits there and "Hums" you can't make it respond to any controls, and the ONLY way to Stop it. is to unplug the unit, replugging back in it simply "Hums" again and will do nothing.
Now this happens because, the STOP Button, is pressed and the "Door Opened", during the Wash Cycle. This should NOT be done. You shouldNEVER TURN IT OFF MID-CYCLE. you should instead, Simply, pull on the handle, to Open the door, the system will take care of everything, after, you close it,and pick up where it left off. The turning OFF, makes the machine "Think" that a New Cycle, is going to be done, before the old one is finished, and resets itself to do it all again. But it still has water, that's not meant to be there so it must dump it out.
Now, the FIX. Take the Dishwasher, out, and tip over on it's side, tip to about a 45' angle. Water will come out from underneath, this is from a small "Overflow" reservoir. this reservoir has an "Anti-Flood" switch. The removing of this water will "Reset" this Switch, and allow the dishwasher to work again.
So what happens, is this, when the STOP button is pressed Mid-Cycle, the machine must "Dump" whatever water is still in the machine, into the "Overflow Reservoir". This water then causes the Anti-flood switch to jam, and this stops the machine, until it is reset,by the above method.