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Repinning an '02 Silverado harness for a '99 Blazer or s10 with 4.3

40579 Views 25 Replies 10 Participants Last post by  jc77
On the advice of Phil I restarted this. Some of my posts will be complete reprints of the last thread. I can add wire diagrams on request Please share pertinent information and ask questions in pm's as to not clutter up the thread.

Ok guys, I have been kinda bored lately since I am low on funds to buy go fast parts. My friend Shane is installing a 5.3 in his 1999 body dropped blazer. I volunteered to repin the harness. This thread will be a tutorial on repinning a 2002 Silverado harness to work in a 1999 Blazer or s10 with 4.3. I will do my best to document and post the whole build along with a spread sheet for repin and such. I will also need help along the way.

His blazer build thread : http://www.s10forum.com/forum/f98/sfbd-99-blazer-help-461568/

His underhood fuse box and ecu will be mounted inside under the dash. I will remove the rear O2's, cruise control, ABS, Windshield sprayers, and any other wires related to these and not needed. The C4 to the old ECU has a lot of unused wires that will get removed.

Here is what I am starting with.

Got to mess around with it tonight, the benefit of working nights and not having shit to do at midnight. I started by stripping all of the all loom off along with most of the tape. Once its all label I will remove every bit of tape.

pretty much bare

So I got a little work done tonight. I started with the red and connectors and unpinned all the wires that are not going to be used. The red and blue pin covers come off pretty easy, just depress the white part at each end of the cover. Once the covers are removed, push the pin up that you want to remove. Lift the white tab and pull the wire and pin out the back of the connector.

There were a few black wires from the rear o2's that went to a large ground splice pack. I clipped the wires as close to the splice pack as I could and will come back to them later to tape up, also from the tan wires from the o2's.

Once I removed the ecu pins I traced them back to there connectors and removed them all or just the pin depending on the connector.

ground slice pack, bad pic

everthing removed so far, rear o2 connectors, some evap and a/c connectors.

lol, so I may have jump started this today. My friend came over. The harness is going in to his blazer. The ecm and underhood fuse buse will be mounted under the dash on the passanger side. The harness itself will be stripped down to the bare essentials to run the motor, no a/c, cruise control. After looking at the un-loomed harness we decided to unpin the entire harness. Using my motor as a template we ran all the wires to the existing plugs and taped it together. We left all the length to cut and solder them to there new homes.

I will try to be more detailed with the c2 and fuse buse wiring, I feel like a ruined a perfectly good how to thread,

Here is a few pics of the taped harness.

Working on the harness and my friends house.

Finishing it up at my house

I just finished up the harness. The C2 underhood fuse buse is complete and I think I will need two more wires to the ecu and that's done. I did mark all the wires that go to the c101 and c4 blk connector from the old ecu. I took pretty detailed notes. As soon as I am done transferring the notes to more legible pin-outs I will scan and post them.

picture of said blazer and test fitting the harness.

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includes c104 2.2 and 4.3
Is there any chance you have this information, but for the 94-95 2.2? I believe they changed after that and were different before that. I've been searching for ever it seems like trying to find this information but I've had next to no luck.

Sorry for Necroposting.
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