Intermittent no-start, 2002 E320s4

[Paul T]

Has anyone run into something like this? 2002 E320 wagon, 210 body, 129k miles. Every few months the car will not start. battery is fine. Both keys work the same. Occurs when my wife is making several stops. When the key goes into the start position, all the warning lights come up, but that is all that happens. No crank. No click.
The car will re-start later, sometimes an hour later, sometimes 5 hours later. the battery is fine, and the car has always re-started, later.
The car has been into a good MB dealer, but there are no deffinitive codes. The possible culprits are electronic Ignition switch, intermittent starter, engine management module, harness.
Until I can get someone with the SDS diagnostic computer at the car when it is no-start, I don't know where to start.
Thanks for looking,
Paul T