Do I need my factory harness?

[1984 t-type]

I’m doing a LS swap and selling parts, do I need my 87 factory harness and computer or can I sell it ? Also are the lights and other non engine functions on their own harness or is it all mixed together ? If it matters or your just interested I’m doing a LSA on either a 6.0 or 6.2 fell free to chime in with other than don’t do it, I’m looking for tips and tricks may even do my first build thread. If I do it will be here and on YouTube thinking about getting into vlogging or however you say it lol

 

[MikeS]

I've never done the swap, but from ones I've seen the original computer was still used to control some of the chassis stuff, and a standalone controller/gm computer from the swap vehicle used for the engine. One even had all the unused engine connection wires tied off to the side, so a 3.8 could be swapped back in. I'd be interested in the build thread, post up the title if its on youtube.

 

[Fat Nat]

All you really need are the starter Sol wire the hot wires with the fuse links to light the fuse box. The rest is all cut out unless your still using powermaster and ac

 

[precizion818]

No.... you do not need the ECM and Harness. I am in the process of removing mine


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[MikeS]

No.... you do not need the ECM and Harness. I am in the process of removing mine


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Share your setup when you can, I may go down this road in the future. Are you able to remove everything intact?

 

[precizion818]

Share your setup when you can, I may go down this road in the future. Are you able to remove everything intact?

Check this out


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[FASTV6HENRY]

Check this out


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Did you replace this with another GN harness or a LS harness?

 

[precizion818]

I did this years again so I replaced it with another harness. This go around, I will plug the hole with a grommet.


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[precizion818]

Did you replace this with another GN harness or a LS harness?

Hey, so I removed the turbo engine harness fully intact. I am replacing half the C100 connector on drivers side with a replacement from Caspers as there are some power feeds required from fuse links originally on the starter that power ignition, fuse box, lights, etc. Outside of that..... the total engine harness came out in tact, I plugged the ECM wire harness on passenger side hole with a grommet. There was a harness connector that went to the passenger side HVAC components that unplugged as well. All relays, and modules came out all together, just had to unbolt them from the engine bay.

For the 5.3 I am replacing it with, I am using a stand alone fuse block that will power everything associated with it. I believe it is a 4 wire connection (12v battery, Gnd, Ignition 12v nand Starter).

 

[70callys]

I tried to backtrack the wires in my harness when doing the swap and keep "what I thought I needed". I ended up not using a single wire, except PCM key on, and starter solenoid trigger from the driver side plug, but it would've been much faster to just run new wires.

Definitely avoid using the stock turbo buick alternator charging circuit for the LS alternator.

I have since done swaps on other vehicles and I start by removing the entire harness then only adding back what I need - results in a cleaner setup.