AnarchySoda

I am in the midst of an LT1 swap into my 1989 Trans Am. I have a whole 1994 Trans Am that I got the engine from to work with.

My question is, does anyone still make harnesses or adapter kits? I have scoured all of the other sites and pages most people refer to for wiring but unfortunately there are a lot of links and pictures that don't work anymore and I am too much of novice to understand the complex diagrams.

Any help or advice is greatly appreciated.

bk2life

did you try google?

88Greg

What exactly are you looking for , A drop on harness that incorporates your C100 wiring ? Or something simpler that you can adapt yourself. The first one is going to be real hard to find off the shelf. You will probably have to send your harness to someone who will make the adaptation.
Is that the pic of your engine as it sits now ? Where do you plan to mount the PCM/ECU ?

AnarchySoda

The pic was from soon after we dropped it in. I'm just looking for anything at this point. Want to put the ecu in the stock 89 location but for now I'm just worried about getting it hooked up to see if it will run. I know there were some members on here that would make one for you or you could send your harness to them and they'd rework it. I think Pocket was one, but none of them seem to be active anymore.

johnw999

There are stand alone harnesses on eBay for an LT1. Here is one that isn't too much:
http://www.ebay.com/itm/LT1-Engine-W...-/282532762294

The harness will need a power source. You'll also need to disconnect your old engine harness. Unfortunately, the old engine harness has things you still want to keep (oil pressure gauge input, tachometer input, windshield wiper connections, alternator/battery connection, engine starter). There is a plug on the driver side firewall. It's called the C100 plug. Maybe you already pulled it. I modified mine to retain the connections that I wanted and to remove the connections I didn't want. This was the end result, and it had a power source for the new ECM.

johnw999

The C207 plug is by the ECM which is under the passenger side dash. It has connections like the fuel pump and reverse lights (you would need to reroute the reverse lights if you use a different transmission than stock). It looks like this:

johnw999

And here are some diagrams of the 1989 C100 and C207:

five7kid

iTrader: (14)

Believe me, I'm as much of a chicken about wiring as anyone. But, I've gotten over that by getting diagrams from the donor vehicle and for my swap vehicle and taking them one circuit at a time - there's no other way to do it.

The Photobucket thing is very disappointing. I'm not going to pay them $399 a year so I can link the pics hosted there. Over time, I'll get them migrated. For the time being, it's very frustrating.

I'd post pics of what I went through to get an LQ4/4L80E graphed into a '57 Chevy, but see above paragraph.

AnarchySoda

Thank you for the info.
I think I have all the wires to the c207 wired to the correct spots but can't figure out where the A, M, and J splice into.
I think I'm also missing a ground as well because when I plug everything back in and put my key in the ignition nothing happens. Headlights don't work or anything. And I'm 99% positive that the battery is good.

AnarchySoda

At this point what I am left with on the 94 harness to figure out where to splice are the
c100 C, D, E, F, H, and J
c210 B, C, and D
c220 A, F, G, and H
c230 A, F, H, J, and K

I know there will be a few of these I won't need. I am not running AC or emissions at this time and I'm mainly concerned with just getting it running so I can move it.

88Greg

The stock Thirdgen C100 is where ALL the power that runs the dash, lights, accessories, everything else, gets into the dash. There are 2-3 thick (10 guage) red wires that were connected to the battery lug on the stock starter. Sounds like you need to connect those to full time batt power.