Ok what you may find here water will have leaked into the base so it has activated the anti flood switch and this brings the pump on all the time even when the door is open.
Im afraid to cure this you need to pull the dishwasher out from under the unit and lay it backwards. This will allow the water to drain out from the base so you may need a towel for this part.
Then stand it up right and once the water is out the anti flood switch will reset itself and this will clear the fault and the dishwasher should start to work again normally from there.
If you need anymore info just get back to me.