Swapping a 1997 4.3 for a 2000 4.3 into a silverado

[lewingjr]

I bought a 1997 Silverado with a 4.3 and 4l60E that has issues with the trans and motor. I bought a 2000 4.3 and 4L60E trans with computer and wiring. The problem I am having is I think it would be easier to use the 1997 harness since there is no fuse block on the 2000, but I want to use the 2000 computer. I see there are some differences in pinouts on the computer, but I haven't found a good wiring diagram for the 2000. I have made a spreadsheet so I can compare pins. I am looking for a diagram similar to the one attached for a 2000 Silverado 1500 with a 4.3. Any other help here is appreciated.

[Dr. Nopps]

Use the 2000 wire harness but leave the old harness & computer alone hapily in it's place. That's how it was done on my truck and it worked out great. (93 Chevy 1500 with a 2001 Astro Van 4.3 non-A/C engine) I think my buddy split the speedo signal into the old harness for the dash to work, I remember it being off a little which I fixed with HP Tuners, but the truck also had larger than stock tires which probably caused most of that. Other than that you should only need a few additional fuses so buy an add on block from Summit or the local Auto store. I think that would be the easiest way to get her done.

[lewingjr]

So you have both computers in the truck?

So far I just installed the new motor and trans and used the old wiring but would like to install the new computer so I can use HP tuners to make some running adjustments.

[Dr. Nopps]

Yeah they're both in there, both harness' too. The old PCM does literally next to nothing and just sits happily in it's place. I think my friend did it that way so he did'nt have to "adapt/integrate" the newer harness into every single aspect of the older vehicle, only where it was absolutely necessary. He had even built his own circuit to bypass the VATS. As "cute" as that is to me I have the most respect for his abilities as he is one of the smartest technicians/mechanical engineers I've ever met or even heard of. If you have any specific questions when you're progressing along feel free to post them here and I can ask him what he did at any given stage of the build. Just try to be very specific and we should know what you mean or are trying to do and I'll be able to keep him sane for a little while longer.