small electrical charge on truck camper frame

Very very interesting. I have felt this a couple times. In the year I have owned this camper. I was definitely not connected to ac when I felt it this last time on the road. I don't know if I was the first time. I could feel the electrical impulse much like static electricity feels. But I didn't get shocked. I could touch any part of the skin of my truck and could feel it. I was driving through 100 degree heat in southern Utah. It was unmistakable on the skin of the truck and camper. I drove a little further down the road and it was gone. I am going to see if I can get it to appear when off the truck. Kind of baffled right now. The first time this happened it was in my shop and I am almost certain it was not static electricity.