Parking lights mystery

Just recently, I was taking a 400 mi trip down south and I stopped at a rest stop to use the facilities. I turned my truck off and as I glanced back to my truck my parking lights came on. I went back to see if I had left the lights on and it was in the off position. So, I turned my truck on again and turned lights on and off again and they turned off. Thought that was weird. Just recently I came home and noticed that the parking lights came on again after they turned off completely when I shut my truck off. It drained the battery and I had to get a jump to start it again. I now have to unplug my battery just so I can go to work in the morning. Any thoughts on what it could be?
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