Slide a flathead screwdriver between the door and dispenser, then apply pressure to force the door to open. If you are able to open the door, clean out the inside with hot water. If this fails to fix the problem, the next step is to replace the part.
Turn off the circuit breaker for the dishwasher. Turn the dishwasher on after shutting down the power to ensure you flipped the correct breaker.
Open the door and remove the screws around the inside edge with a screwdriver. Place the screws in a safe location until you are ready to reinstall them.
Close the dishwasher door and pull off the outside panel to access the soap dish wiring.
Unplug the dispenser motor from the dishwasher by gently tugging on the wire harness. There may be more than one, so pull off any wiring you see.
Remove the screws that hold the dispenser cup in place and pull it off the door.
Insert the replacement dispenser in the hole in the door and secure it with the screws. Attach the wire harnesses to the unit before reassembling the dishwasher door.
Turn the power back on and run the dishwasher. When the wash cycle starts, open the door to see if the cup opens properly.