Wow, I completely forgot about this post. I will have to update and edit my list, because I just got the truck done in April of this year! As far as the OPS goes, the '02 harness OPS plug plugs directly into the '02 LM7's OPS.
Take a look at this Facebook page, it is the reason I didn't pull out ALL my hair and the truck didn't end up in a junkyard ;-p
https://www.facebook.com/groups/607787819352393/I get ya with the pulling out your hair. I'm pretty capable, licensed mech for over 35 yrs and swapping a LS into a 98 1/2 ton has to be one of the more challenging swaps. We're keeping all the emissions, anti lock brakes...the whole deal. Making all the 98 systems hook up to the 02 is so far from a stand alone 4 wire harness it's in a different world. Just try to find pin outs on the 2002 under hood plugs, other than the red & blue pcm, the eng harness blk c2 & the c100 plug...good luck. I don't even know how much time I've spent searching for the uhfb gray c1 cab harness plug pin outs. Right now my current mystery is what to do with the org/blk fuel level sensor ground wire on the 2002 harness. This is the blk wire out of the fuel level sensor on the 98 sender, (which we're using) it just goes strait to ground on the frame. The 2002 harness ( which we're using ) goes to the blue pcm plug pin 80. I tell ya I can't wait to do this swap into a pre computer car. There's page after page after page on how to do a stand alone harness out there. Try to find all the info you need to put an LS in a 98 chev truck. Got to be a very popular swap but unless you can read schematics, that actually show plug #s, pin outs, colors ect then forget it. There are so many wires and circuits to match up its a real challenge. One little tip is to pay attention to circuit numbers. A lot of them match up....some do not. So that's my little rant, im getting close. When I get this all figured out, im going to write it all down, in plain English, black and white...this wire goes from plug so & so, pin # , color & circuit #, & function to What ever the corresponding plug , pin#, color, circuit & function and destination on the new harness is. I'll stop this post now; getting a bit carried away lol. There are other issues but I'm going to check out your Facebook link first. Thanks very much for time .
