I Have A 1999 Dodge Ram 2500 Cummins Turbo 24 Valve 5 Speed 5.9 Litre Truck That I Have Switched With A 1994 12valve Diesel Engine. I Need To Know Either Two Things. Does Anyone Know How To Hook Up The 1994 Wiring Harness(12 V) To The 1999 Ecm Unit?
If Not, Can I Buy A 1998.5 12 Valve Engine Wiring Harness So That The Computers Will Communicate Properly.
We Have No One Around Here That Knows Anything About Diesels. I Knew Enough To Get The Engines Changed But I Am Stumped On The Electrical. Also Do You Know Anyone Around Greensburg, Indiana That Might Be Close Enough To Help Out. Thanks!

 

12 valves don't have an ECM but they have a PCM.
The engine doesn't need the PCM to run but if you want gauges, wait to start grid heaters A/C and auto tranny shifting you'll need to pick up a '94 PCM and harness.

 

The problem is will the PCM talk correctly to the BCM to get the tachometer to work.

 

we couldnt get it to work on my 03 when we did it cause i believe the 24v and the 3rd gen motors take a reading off the cam sensor and the crank sensor

 

What did you end up doing?

 

I don't know how it was done, but my friend has a 97 with a 24V swapped in and all the guages work fine on it, I don't see why it couldn't be done the other way around. Sorry I can't help ya though.

 

I would just rip out that cluster and fab up a plate and mount some sweet aftermarket gauges to it.