Hadn't seen anyone post about how to do this so I figured I would since I just did it to my car. (sorry I know my fugly little hyundai isn't a Ram but the 12' doesn't have faded headlights, but the application is the same)
I previously did this to my 99' ram before I sold it. I picked up this little beast a couple days ago for daily driving. The headlights sucked and I couldn't justify spending a dime on this thing for new headlights.
I started out with 1000 grit wetsanding paper with soapy water. This is how it should look after it's wetsanded.
I then moved onto 2000 grit wetsanding paper, the key with wetsanding is as you move up in grits you have to sand more than you did in the last step. If you made 4 strokes with 1000 you need to make 5 with 2000 sort of thing. It should look a little bit clearer than it did after the 1000.
I then took a shop towel and hit it really hard with rubbing compound. I have a polisher I could have used but I was too lazy to hook it up. A power polisher will bring the shine out even better.
Simple as that, did the fog lights as well.