Obs to Lsx wiring made simple

Ok so if any of you guys have been keeping up with my build its been a long road. But i have found the easiest way to run the wiring for the ls engine into a 96+ Truck. This will only work in those trucks. what i have found is that you can remove the pins from your factory harness and install them right into the ls harness and pcm. that way you will be using the OBS fuel pump relay, VSS signal, Check Engine light, and brake signal.

basically if you decide to do your own harness or have one made you will remove from the green connector completely

9 - Fuel Pump

46-Check Engine

16-4wd low (4wd only)

blue connector

33- brake signal

then from your stock obs harness you will remove the following pins and insert them directly into the ls harness

Black connector plug

1 fuel pump

5 Check engine

10 Brake signal

23 4wd low (4wd only)

this saves you from having to cust and splice wires and makes for a seamless integration. as far as the starter you can reuse the factory PNS switch and obs solenoid wire which should be purple.

the other connections from the harness like ignition and constant power should be pretty straight forward. the only connection i havnt figured out is how to make the tach work. if anyone has info please share.

if i missed anything or if anything is incorrect im pretty sure some more experienced guys will chime in.

Awesome! I wish someone had this for the 95's.

This is awesome hope to do the swap into my 98 Yukon soon

For those of you with older than 96's. If you can read wiring diagrams, I'd suggest going to www.alldata.com and spending the few $ on a subscription for both the donor and your vehicle. Their diagrams can be confusing as though so read and re-read them to make sure you don't smoke your ECM. This is what I did with my 88 and it takes some time, and lots of research to make sure you're not leaving anything out. But it's a lot simpler than just going at it blind or by wire colors that may or may not exist in your application.


But this is handy for a 96+. I'm eyeing a 8.1L for my 00 that may make it in this summer, so this is gettting bookmarked.