greetings all!

Getting pinout info for really recent engines can be tough, I've been there/done that. What's worked best for me is to work with people that work at GM dealerships, whether locally or online. I've gotten parts guys to print out connector info, & I've gotten other info from guys here on this forum. It took me a while (several weeks), but I'm pretty sure that I now have most or all of what I'll need. (Going to be working on wiring really soon now.)
I guess you've just gotta combine politeness with persistence, & what you're looking for will eventually turn up.

