300CE ignition switch sometimes does not turn over the engine. It occurs when I have driven to a location and come back about rtwenty minutes later. I can hear the solenoid clicck (I think) but no effect on the engine. I have tried wiggling the gear lever in Park and Neutral but to no avail. Then, about five minutes before the AA are due to arrive (20-40 minutes), it starts normally. If anyone has any ideas on the matter, iwould be grateful to know.