kitchenaid DW won't start

model KUDPO1FLSS6 dishwasher with the user buttons on the top of the door. I have power to the unit, and the door switches both test good using Ohm meter, but the unit will not start. Lights on the control panel light up (normal, heavy, energy saver, etc) when pushed, but when I push the start button and close the door, nothing happens. None of the lights blink, they just go out after I close and then re-open the door. I don’t know how to test any other components other than the door switches. Any help appreciated. Thanks in advance.