Freightliner starts by itself...

[Waterloo]

My buddy has a 2000 Freightliner FLD Condo, Cummins N-14. The truck while sitting parked with the key in the ignition, not running, no one near the truck, and the darn thing just starts turning over. The starter just starts turning and turning and turning. First time it did this my buddy pulled the battery cables, the batteries actually started on fire. This was at a shipper, the truck was parked, not running in the lot, he was just coming back to the truck from the office.

The second time, truck was off, he was chaining down a coil when the truck started. He had his bar so he got under the hood and smacked the solenoid on the starter with it and that shut down the starter.

I have never heard of this, other than on a car with one of those aftermarket car starters. he said there was nothing like that on his truck. What do you guys think?

Oh, it has an ignition for the key, and is started with the old style button on the dash. I'm thinking a faulty ignition switch. But still cannot wrap my head around how this would happen. Any ideas?