Factory Service Manual
I have one I downloaded for a 2008-10 Challenger but I can't find where I got it now to give you a link. It's seems to be an ok version, but not completely sure it is a real copy of what Mopar would have put out. Either that or they have slipped in their documentation.
I did run across one comment by a guy answer a similar question. He had a friend that was a service tech or something and he asked where to get a FSM and the guy said to go to AllData. It's a subscription instead of something to download, but you can print stuff. That's where I got a lot of the wiring diagrams for my 5.9 SMPI swap into my '91 Dakota.