I have an 04 1500 with the 3.7L V6. It has a cracked head so i bought a 4.7L V8 to swap in it. Ive got everything with it, trans, harness, pcm, intake, etc. The donor truck was also an 04 but not sure of the actual mfg date. The harness that came from the donor truck seems to be completely different than the one currently in my truck. There is a big plug on the driver side that my truck does not have for instance. Is it possible to put the harnesses together to make it work for my truck or can i get a different harness that can plug directly into the existing wiring in mine?

 

If they are both 04's, the harness *should* be the same....... Does the 'big plug' bolt to the TIPM??

 

No. The PCM or TICM whichever you wanna call it has 4 plugs on both of them. The v6 and v8 pcms. The big connector was on the drivers side of the engine compartment. It connected to another harness that went into the bulkhead and behind the dash.

 

TIPM= Totally Integrated Power Module. Does your truck even have one???

That large bulkhead connector should be down by the steering column somewhere, cleverly concealed by the brake booster, and a host of other fun stuff they stick under the hood these days. Might be easier to find it from inside the truck.