Turn off power to the dishwasher at the circuit breaker.
Release the door latch and open the dishwasher door to listen for the squeak. Isolate the sound by listening on one side, then the other, so you know where to work.
Take out the screws in the left and right edges of the bottom access plate below the door. Pull off the plate and set aside. Look at the hinges where they enter the sides of the cabinet along the bottom left and right sides of the dishwasher door.
Lower the door to the horizontal position, parallel to the floor.
Spray a short burst of silicon-based lubricant on each metal hinge that squeaks at its top and on its underside, below the space where the access panel attaches to the appliance. Raise and lower the door a few times to work the lubricant into the hinges and stop the squeaking.
Reattach the access plate with the screws and restore electricity to the dishwasher.