Just completed this install today. At Pick Pull I pulled the entire ceiling harness right down to the plug behind the fuse block on the drivers side. I also pulled the HomeLink and auto darkening rear view mirror.
Out of curiosity and before doing a bunch of unnecessary work, I unscrewed the fuse block and pushed it back out of the way so I could squeeze my hand in there. Unplugged the existing harness and plugged in my salvaged harness, hooked up the computer and reconnected the battery, started the truck and...EUREKA!!! She fired right up!!! Let it run for a bit to see if it would blank out like one of the previous posts but it sure didn't. All the data was there. So I reset the existing data by going to the fuel Econ and held both buttons down for three seconds. Pushed the pedal a few times and watched the current fuel Econ fluctuate, fuel consumed clicked to 0.1L. Content with that I took to swapping the harnesses.
If anyone does do this mod, when removing either the salvaged or your truck harness, take care when removing the clips into the truck. A few of mine broke off in spite of being careful so it was nice to have a few from the salvaged harness to swap cuz some of them broke too.
Also, I couldn't find a way to pull the large harness plug up out of the corner of the dash, so after carefully photographing the wire placements, I taped the two halves of the wires together to keep them separate then popped all of the wires out of the plug and pulled the harness up out of the dash. I also had to do the reverse with the new harness to get t back into that tight corner. I also taped the small metal connectors on the end of each wire into a bundle to protect them from getting bent when I stuffed them back into the dash. Reinstalled the wires into the plug once in place.
Up top, IF you have a harness with the Homelink and you do want to install the Homelink, there is a larger 6-pin plug that is grey (in mine) not black like the 4-pin plug in our CCs. The colors are the same but placement is different. Also the 6-pin has a dark green wire for the Homelink and one open pin. For these, I popped the wires out of the Console end of the 4-pin, and put them into the places where they should be in the 6-pin. I should mention that I had to cut this 6-pin plug out of the salvage truck or else I would have had to take the whole console. Took some figuring out but I made it all work and look as tho it was factory and I couldn't be happier. Took a stroll down to DQ for a Blozzard and all the data read perfectly.
Moral of the story, our trucks have all the correct wires coming to the plug behind the fuse block, but not up the harness to the computer. Swap out the harness and you have a plug and play mod. No splicing into the serial data or anything. I'm actually surprised that no one has ever tried swapping the whole harness, but I'm glad I gave it a shot and even more stoked that it worked.
'02 S-10 CCMods include:
ZR2 rear axle, 31" shoes, 2" rear lift shackles w/ front torsion tweak, 2.5" RCL, 1.25" front spacers, Rocker guard, Tow Package, Roof Rack, light bar, heated leather seats, front tow shackles, trip data computer upgrade, 5-speed transmission swap, fuel tank skid plate, carbon fibre skid plate package, K&N CAI
Upcoming are fender flares, iron front diff swap, possible 2" body lift