Look at the latch on the top of the door. If the door latch is dirty with residue or dishwasher detergent, the latch will not close properly and can get caught in position. Use a clean, damp cloth to clean the switch and wipe away any residue. Dry with a towel and wiggle the latch to ensure the latch moves freely.
If the dishwasher control panel has been locked, the door latch will be engaged and the door will not open or close properly. The control lock is indicated by the “Control Lock” light flashing three times when any control key pad is pressed. Hold “Control Lock” for three seconds to release the control lock, and then push the door closed as needed.
If the Whirlpool dishwasher door remains stuck in position, press an Allen wrench down on the latch strike retainer brackets on the metal ridge of the dishwasher. Release the latch strike and reach in to move the door latch into the lowered position, and then reinsert the latch strike into the slots on the dishwasher door.
Sometimes the door latch microswitch is not activating correctly, which can cause the problem. Disconnect power to the dishwasher and then find the microswitch on the side of the door latch assembly. Disconnect the wiring harness connectors by pulling the connectors at the terminals, and then pull the two plastic retaining tabs out. Lift out the microswitch and replace with a new microswitch, and then reassemble the unit. Note that this process should only be done by those skilled enough to disassemble and repair the dishwasher. Contact Whirlpool for assistance if you are not confident in your repair ability.