So on the front of a 2006 Dodge Grand Caravan, right towards the bottom, there is a wire grate kind of thing covered by a flimsy plastic bar with parts of it visible above and below. Today as I turned of the van, I heard a hiss and as I looked into it I realized there was smoke coming out (or some sort of vapor). I located the hiss to be coming from a hole in this grate behind the bottom of the front bumper that can be seen on this diagram right above the number 4. Does anyone know what this part is? or what it is leaking?

 

It sounds like a rock hit your air conditioning condensor when you were driving. If your AC is not working now you can pretty much confirm that diagnosis. You will have to have a new condensor installed if that is the case and the AC system vacuumed down and recharged.