Our diswasher was leaking bad , when I opened the door water was still filling., it took a minute to stop, I stopped it and pumped the water out. Checked the drain pump OK, float works, but I dont know about the float switch, or the fill pump switch.. something is wrong???
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Replacement parts for FRIGIDAIRE FDB836GFB7 Dishwasher | AppliancePartsPros.com
It sounds like your water valve is slow in closing.
It should have stopped as soon as you opened the door.
You could remove the kick plate, start a fill and then deactivate the overfill switch by raising the actuator. It should stop filling immediately. If not replace the water valve.
Be careful as this is a live test and you do not want to get a shock.