I have a 2008 Dodge Grand Caravan with 25,000 miles. When I get home after driving about 60 minutes, I’ll leave the car running, get out and open the sliding van door and unload my books. If I get back in the car, before I have a chance to buckle my seatbelt, the windshield wipers begin to sweep back and forth and then all of the dashboard alarm lights flash. This doesn’t stop until I turn the car off. When I start it up again, no problem. It’s happened several times. The van is at the dealer. The technician looked at me as if . . . well you know.
Maybe some new fangled safety stuff glitch, if they find no problem try turning it of before exiting the vehicle and see if that solves the problem.
Aside from the windshield wipers, I would think waterboy is right, your butt is not on the seat and the seatbelt is disconnected while the car is running, then you get back and the lights flash warnings. Have you ever fastened the belt and waited to see if anything stops?
I would see what fuse protects the wipers circuit, and see if that fuse has in common any part of the dashboard display. If it does, something unintended is going on with that circuit.
If it doesn’t happen when the mechanic test drives it, you’re probably not going to get any satisfaction from them. If they can duplicate it – well I have no real clue. It might be connected to the seat belt alarm, but there would have to be a short between in at some other systems. Maybe start by pulling the fuse on the seatbelt alarm and see if that stops it.