Here is something I found, they talk about a wire near the ac compressor. Loose or dirty grounds can cause a host of problems that would blow your mind, seen it many times at the Cadillac dealer. Dash going crazy, buzzers and codes....cause, loose ground on engine somewhere.
http://www.dieseltruckresource.com/dev/need-help-truck-wont-start-t176493.html?&highlight=2005+Camshaft+sensorI'd check that first, cheapest, then go the other way. Yes, dealer has the most knowledge for the most part, EXCEPT if you have an authorized Cummins repair facility near you. The dealer near me put on a new injection pump and bent the fire out of my timing cover and it leaked oil all the way home. As a previous Cummins mechanic at a dealer I wondered why it was he had used a prybar on my timing cover when Cummins supplies a nice hole in it to unbolt the VP44. After the dealer bought the parts and said they could install them I laughed and said, the heck you will and brought them home and did it myself.
Your other option(my ideal choice), authorized Cummins dealer, not dodge dealer. Place near me is well spoken of by all the folks around here and where most farmers/working folks take their Cummins to be repaired. The dealer for the most part is good but you do have techs/mechanics that are in the "hack" zone. I've seen some things done by co-workers that would make you cringe.