I was able to source a laramie harness in good order that does service a few additional features than my slt of the same year 2500 crew cab.

I completed the harness, it does go into the engine bay a fair bit and made sure once complete all grounds were set, connector were clicked and battery terminals were solid.

In the end the experiment could have been a bust not certain but it would seem just about all the error codes that could come up have, including fly by wire and I made especially certain that was secure so limp mode it is and not sure by my EFI Live Autocal won't clear the codes not sure if it's meant to but it does have a clear DTC's as an option.

Just curious if anyone has run across such a situation some addition codes are lamps out on mirrors, 4 wheel drive, low fuel with 1/4 tank still in tank, service, thx for any feedback