I’ve got an 02 Ram with a 5.9 Cummins and 5 speed manual trans. I just rebuilt and reinstalled my starter. When I turned the key I had no power to the dash. All of the fuses under the hood checked good. Then I put some battery post shims on the negative terminals because the cable clamps were still loose after max tightening. Now, some of the time, when I turn the key, the dash lights up, but when I try to engage the starter, everything goes dark again.

Where red do I need to start looking for the problem?!?!

 

You might get better response in the 2nd Generation forum, but in the meantime after you've load tested your batteries, I'd start with the problems you've identified already, insufficient grounds...And use a test light for checking any circuits......Ben

 

I unplugged the light and everything began to work. Coincidence, or what?

 

Which light did you unplug? Where?