tracing power to pins on a Marklift board

I have a mark lift ch 60c aerial lift that is having some an electrical problem that I cannot figure out. I have wiring diagrams but they are fuzzy. There are two boards total and from what I see the power travels through this analog board it has to reach the second board however I'm having a hard time figuring out where the power would even come into this board at, the one thing I do know for sure is that connector j12 pin 318 is what supplies the power to the other board any help on this would be greatly appreciated. I have attached the main diagram but I have breakdowns of some sections of it as well and pictures of one of the two boards.