You may want to start the troubleshooting from verifying the power supply to the dishwasher.
Remove the toe panel and check the power cord connections to the dishwasher junction box. Make sure that the power cord hot (black) wire is connected to the dishwasher black wire, the neutral (white) wire is connected to the dishwasher white wire and the dishwasher is properly grounded.
Check the wires at the door bottom edge for any physical damage.
Check the on-off switch for continuity in accordance with the wiring diagram.
Thanks for the advice. I checked power and wires and all were okay. I checked the switch and it appeared not have continuity between 1-2 when closed, so got a replacement power switch P/N 175338 - which curiously seems to have the same issue with respect to continuity. Hard to believe a new power switch would have same problem as the old.
In the process of testing dishwasher with both switches, I noticed the same behavior with each - illegible, faint flickering of the display when the unit was powered on - but no operation whatsoever. Should I be looking at the control or the display modules instead?
Check for 120 VAC between the wire connected to the terminal 3 at the on-off switch and the ground. If the reading is correct, check for 120 VAC between this wire and the wire connected to the terminal 1. Post the results.