wont start but specific CAS test ?? 87 NA

never has a start issue in 10 yrs but this weekend it happened. car stalled, then started and ran again for a while (1 hr), now no start at all. Fuel pump/pressure is OK. Also checked all the switches/interlocks. Car cranks just no start

Now trying to sort out the electrical components and left with PT or CAS. When following the FSM on CAS testing, it appears I do not have 12v on the harness. I tried to figure out where does that source come from. They say check main relay, so which one is that and where?

Between my ignorance on reading the diagrams and maybe FSM lack of details I cannot figure it out. Relays called hook up and ignition are near the fuseable links and another is at the fuse box inside the driver seat. Please any help cause this is pissing me off!