Drain pump runs constantly

Dishwasher Repair
,
1

My frigidaire dishwasher drain pump runs constantly. Even when the system is not set to run on any cycle and all indicator lights are out, if you close the door, the pump starts immediately. I have poured water in to make sure that it does drain and it will drain but when you open the door and it stops some water does come back in from the drain tube. It is only visible if you take the bottom drain filters out. I have tried turning the breaker off and resetting it but the pump will still run as soon as the door is closed. I was wondering if this is a problem with the control board or maybe some sensor telling the unit that there is still water in the bottom? Thanks