The thermal fuse shuts off power to the dishwasher if it overheats. If the thermal fuse blows, it will prevent the dishwasher from starting. To determine if the thermal fuse is defective, use a multimeter to test the fuse for continuity. If the thermal fuse does not have continuity, replace it.
The door switch prevents the dishwasher from running while the door is open. If the door switch is defective, the switch will prevent the dishwasher from running even when the door is closed. To determine if the door switch is at fault, use a multimeter to test the switch for continuity. If the switch does not have continuity, replace it.
The door latch ensures that the dishwasher door latches shut. If the door does not latch properly, the door switch might prevent the dishwasher from running. If the door latch is broken, replace it.