Question 2007 Cat C7 Starter Gremlin

[Diesel Pusher]

We had landed at our final stop yesterday before home and settled in when after about a half hour, the starter on my '07 Cat C7 on Freightliner chassis activated without the ignition key, it was in my pocket! Everything on the dash was dark, no gauges activated, Allison key pad was dark, parking brake engaged. Starter would activate and turn the engine over at random time intervals. I did put the key in and cycled on & off a couple of times but not far enough to start the engine but the starter activated on its own and the engine started. Intervals ranged from 5 minutes to over 30 minutes before engaging again. This went on for about an hour while I tried to figure out what was happening. I turned the main battery switch off to no affect. I then disconnected the negative cables from the chassis batteries and unplugged from shore power (Xantrex 458 maintains chassis batteries). I've tried to trace cables for chafing looking for exposed wires... no luck. Maybe the starter solenoid? I've heard of similar instances with Corvettes and Ford F350 diesel trucks. Can anyone offer any insight?