where is the drain plug for the radiator

Should be located on one of the bottom corners or bottom middle of the radiator, either in the front or rear side of the corners. It may be covered by a plastic air dam or under-engine fascia panel that may need to be removed to access the drain plug. Chrysler has also been known to hide their drain plugs behind the grille on the front of the vehicle so if you have no luck underneath the car, see if anything is visible behind the grille.