The 2 most common part(s) or condition(s) which cause the symptom Dishwasher won't start are listed below starting with the most likely. Check or test each item and watch any available videos.
RepairClinic Item # 2210680
If the dishwasher does not start, the door latch assembly might be defective. These are normally made of plastic and cannot be repaired. If the door won't latch and the door latch is broken, replace it.
RepairClinic Item # 1550665
The main control board provides power to nearly every component of the dishwasher. If the dishwasher won't start the main control board might be defective. You should first check for more common parts. Many times control boards are replaced unnecessarily because the problem was not diagnosed properly.