im in the process of building my swap harness.i have all sensors wired, all pcm wires labeled by the 411 pin out. im thinking the pcm should have keyed 12v, constant 12v, and ground. blue 1& 40 & red 1 & 40 are ground & blue 20 & 57 are battery +. are these grounds just chassis grounds? are battery + going to or coming from the pcm. what pin is keyed 12v? any help would be great.

 

All 4 grounds goto the chassis ground (in the factory harness, they all get spliced into the same wire)

Blue 20 and 57 are Battery + voltage.
Blue 19 is Ignition voltage (Key on)

This is an excellent source for wiring diagrams.

Good luck!

http://lt1swap.com/2001_ls1_schematic.htm

 

Thanks for the reply. I was thinking that after reading the updated harness thread but wasn't sure. Don't have much luck when guessing.

 

This may help you out a bit too:

https://www.thirdgen.org/forums/ltx-...s1-pinout.html

I enjoyed doing my harness actually.