what if your grand caravan does not say auto on the head light switch, how do you put them on auto?

Check your owners manual

Automatic Headlights were considered an upgrade with one of the safety packages. We just purchased a 2012 and found this out too once we got it home. Pretty silly not having auto lights, when GM has been doing this for over a decade. You can possibly replace the headlight switch with one that include the "Auto" position. See the linked thread for others who have done this: http://dodgeforum.com/forum/dodge-caravan/332882-2012-sxt-no- automatic-headlights.html