04.5 ECM Wiring Harness Question

Happy to help.

I don't understand why they put such a conglomeration of circuits in those connectors unless it's just their location. When I get time, I'll try to run down the circuits a little more and see exactly where they go.
 
That would be awesome!
I was scratching my head the other day thinking, man these Cummins harnesses are complicated! Lol. The duramax I swapped wasn’t near this hard to figure out. But it seems there’s a little more info easily accessible to rookies for the duramax stuff...
 
Been watching this thread. I have my 05 down for some engine maintenance and searched the other evening for those connectors, couldn't come up with anything in the engine bay for them.

Not sure if it helps, I have an ECM on the shelf. Came from a 03 gas engine truck. It's a Mopar reman unit and was working when removed. Let me know if you might need it.
 
Ok, thanks Red Sleeper!
I’ve got an 04.5 ecm heading this way to try. It’s a known hood one as well. Hopefully it’ll give me some good results!
 
Ok I can’t believe it, my friend I got all of the harness from had another truck there at his place. Ran over there and actually found the other side of the harness! It runs along the bottom of the drivers side cab, connects to the fuel sending unit and of course goes to the rear lights and what not.

While there I saw the fuse box was a little different than the one I had. It had two connectors under it that I was curious about on my harness. So I robbed the fuse box, came home and connected it. Sure enough, the dash works as it should, and I’m able to communicate with the ecm now! So soon as I can make it back to finish pulling the tail light and fuel sending harness, I’ll see if the lift pump will kick on like it should.

Thanks a million so far for your help guys!
 
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The ECM for a Cummins is a Cummins part. The gasser ECM wouldn’t even plug up.
 
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