Where is the plug located which is used to plug the van in during extremely cold weather?
I think you are referring to a heater block. Not every car comes installed with one. If there is one it would be under the hood although not sure exactly where. If it doesn't have one then you can buy a heater blanket that is basically a blanket that you put over the engine at night and plug it directly into the wall.
Search Mazda MPV Questions
Mazda MPV Experts