It Looks Like The Type Of Plug-in You Would Find On A Laptop, Computer etc. its a 3 way, it would plug right into a house outlet, anyone have any idea what this may be for?
That is an engine block heater, but they are usually just on diesels. That's kind of weird, maybe the truck came from Alaska where it's really cold all the time. The heater heats the oil, and some times the water too, for easier starts in cold weather.