Actually even without the pinout you can trace like 75% or more of the circuits out by simply comparing the traces to each other while following them around the board. Grounds common to all needs will tell on themselves, i.e., you won't find power going to both backlighting and say oil light from same circuit, so they must split. The splits determine power into various things. How I do the simple early instruments like these have. I can pretty much trace out every single one. Then draw out your own pinout.

Just an idea but it works. If you have the skills to understand a pinout you are good enough already to do it.

I have the cluster at home and will be tracing out the leads to figure out that wiring. It's just a pain to trace out the original engine harness when all of the wiring is out of the car. I could plug it back in and hook up a battery if I have to.

Yeah, under the dash. I wish they were kept separate but both connectors share lights and engine related stuff

  That would be awesome, I still need wiring diagram and/or pinout to figure out why cluster isn't working.