Welcome to GMT Nation...
Most of what you will want to know for creating an
"All In One" (AIO) Test Harness is thoroughly documented in the linked Threads below. You'll just need a little patience to pick out the sections that pertain to your
LS Platform Engine ...look for
"The Sloppy Mechanic" references along the texts and Copy Paste the
Harness Pin-Out-Layout suitable for your
LS Motor P01-P59 ECMs.
Also...visit the
HP-Tuners Thread over and just below the
Tech 2 Area from the
GMTN Main Page and watch the Videos linked there for the
"Real World Set Up" and check back in on your own thread here from time to time with any questions you want to discuss. It is pretty much all there... and again... it will just require some patience on your part to read through it all.
Start HERE:
BIGGER EDIT: 04/24/2019 For THE BEST On Topic Solution ...Go Directly to Post # 42... BIG EDIT: This Thread originally was to cover creating a Test Harness to use exclusively for diagnosing and repairing the GM Trailblazer and Envoy, etc Instrument Panel Cluster and Components... but...
gmtnation.com
...then visit HERE:
This is to share your experiences of the use of the HP Tuners tools
gmtnation.com
Please ...Don't request for any "Custom Engine - PCM - HP Tuners Test Harness Builds", etc. The whole point of my Documenting as many of the intimate aspects and details of Creating these Unique Test Harnesses... was to encourage OTHERS to make their OWN. I'm sure you understand.