This is a cut and paste from an old post I made when my pressure went to "0".
I cut and pasted this from a reply I made 3/09 so the price may be more or, may not be available anymore. Stick with the Cummins parts house.
When I found out the part (P/N 4076930, "switch, pressure" $11. 37, also required was, P/N 3164755 "cable, electrical" $12. 68) that I bought from Cummins would turn the gage into an idiot light, and only after I had to "re-program" per the instructions. I returned it and called the order in using the part number (4921511 "sensor, pressure) I found on TDR and had it shipped to my house - took about 4 - 5 days well worth the wait. And, to keep the dealer out of my truck - priceless!!!!
Some other info as well, "Bin Location 614/004" in case someone says "They can't find it so it's not available". The guy at my Cummins parts is a good guy and knows his stuff, but when it comes to locating the part on the computer he looks for the "superseded by" number and that's that. Kind of a bummer . . .