I don't know if this will apply to the Dodge Cummins diesel Rams but maybe a heads up here.

I had problems with a brand new ignition switch when I did my diesel swap. It was your basic cheapo aftermarket switch that worked fine cranking my 360 V8. When I installed the 4BT and its massive 6BT starter the crapola switch couldn't handle the amperage, would almost crank over but like a nearly dead battery not quite.

2 other guys had the same problem on their swaps using new aftermarket switches! I installed a 50 amp pushbutton with either 10ga or 12ga wire to starter relay and then they did the same, problems solved.

Just thinking maybe this new switch in the OP's truck can't carry the amperage. Might get a helper and use a test light at starter wires and see if starter is being energized from switch. If so it could indicate the problem I described - junk switch!

 

I can't thank you all enough for the support. I found the culprit. In the link taterfarm suggested I look at there is a picture of a triangular shaped rubber connector that has a large gage wire that connects to the pos of the batt, and has several wires out the other end. The orange wire in that bundle was burned in 2. I jumped it and she kicked right over. Definitely have a short somewhere because I get sparkles when ever I remove the neg bat cable. But she starts and moves and the meter readers in downtown Minneapolis will not have the pleasure of towing it away...I think the harness can be saved, I really like the write up in the sticky about cleaning up all that spaghetti & replacing the links...just don't know if I'm the man for that job.

 

Those wires coming out the triangle are fuse links. You need to put inline fuses in or you may let the smoke out somewhere else. Might be q good idea to disconnect the battery if you think there is a short. Hate to have it burn up.