Truck is a 03 1500 4x4 4.7l. I already have used 03 5.7 with all acc, apps, and wiring harness. The truck I got everything out of only had the tcm. From what I read on alldata at work the tcm and pcm don't have to match. It stated all you have to do when replacing a tcm is do a quick learn for the tcm to communicate with the pcm. My question is has anyone tried this? I'm pretty sure it will work. It's just that Im going back the salvage yard where I got everything this weekend and want to make sure I get the right stuff. btw T-muns thanks for the good build thread it helped big time. I did not want another 4.7 mine took a big crap. I will post pics.

 

You can get a 2004 ecm for $50.00-$100.00 . Nothing from the 4.7 engine harness will plug into the Hemi. Fuel injectors ,Coils ,evap purge ,fan ,alternator ,knock sensors , all have a different plug.. It would be a lot easier to get a 04' ecm and wiring harness and just plug everything in , then plug it into the white plug under the dash.. I paid $250.00 for my harness and $75.00 for an 04' ecm..The only difference between a 03' and 04' is the EGR Valve..If you stay with the 03' you will have to use a TCM and ECM and there's not a good tuner out there for a 03'.

 

I have a 04 5.7 wiring harness also but read that using a 04 wiring harness and pcm is a lot harder to do than the 03 stuff. As long as its pretty much plug n play like the 03 5.7 swap t-mun did I would do the 04 pcm and harness, but I already do have the the 03 5.7 harness and tcm. Just not the pcm. What kind of wiring issues are involved with 04 harness instead of the 03?

 

The main difference between the 03' and 04' is the tcm . The EGR can be by passed..When I put the 03' engine in my 01' Dakota I didn't know anything about any of this Dodge stuff so I chased each wire one at a time from the Dak to the 03' ecm-tcm harness..It was more than a pain - it took 6 months..I thought I was going to have to do the same thing when I put the 04' Hemi motor in my 02' Ram..But when I ordered the 04' harness it was pretty much plug and play..It took 2 days..

 

The engine I have does have a egr valve. After checking everything the engine is a 04 along with the wiring harness. So besides what I have all I need is the ecm, correct? I won't need anything else? What all did you have to do with wiring to get the engine and everything else to operate correctly like cruise and all that? Thanks for the help.

 

Unplug your wiring in the truck from the headlights to the dash and install the 04' . It should plug into the white plug under the dash. Remove the old ecm and tcm and install a 04' ecm . plug it in and go..As for the cruise , I haven't figured out how to get mine working yet.. You will also need to install the fly by wire box under the battery tray and plug it in and run the excellerator cable to the excell. pedal. You can get some tips by visiting some of the threads on this sight by people who have already done this swap..There's an 04'Hemi wire pin out on my Dak. Hemi build, That will show which wires go to the cruise and anything else you might need to look up..Check out 02' Ram get HemiDak-Quads 04' Hemi thread. and DDIRI Ram Hemi Transplant.
Once you've got you're wiring done , you'll need to pull the evap purge system from under the hood of the Hemi truck. hook it up on yours. Then cut the fuel line under the cab where it's steel . Cut it in the same place on both trucks with a pipe cutter. Once you've set the motor in and your ready to hook up the fuel line , slip a 6" inch hose over both ends of the cut fuel line and put two hose clamps on each side..I put a little JB weld on the steel tube before I slide the 3/8 I.D. hose over the cut tubing. It lubes it and helps it not to leak once it's dry and the hose clamps are tight...