First questions:

What is your battery gauge doing from a fresh charge to when the car kills?

Will the car discharge the battery just by sitting at the same rate that it discharges when running? This may limit our search to a fewer circuits.

Now for some info that may be interesting. This is based on my diagrams and experience and not on fact since your car is a different year. But it looks like the big fatty wire is basically for the starter and alternator. That's all those do. The next biggest one (with the squared eye) is for everything else. It powers the computers, the gauges, the clock, the windows, the lights and anything else that the car needs to power. So what about the other two. They are for accessories. Things like ABS and other things that would not be included in the standard wire-harness for that car. My car has one for the ABS and another for the Turbo Plus system. I would assume that one is for your ABS and one for something else.

 

I just did the reading on the battery while the car is running... 12.1 V
Titan Joe, The one you mentioned as "with the squared Eye"... That is a bundle of 3 cables and the largest of THOSE does the arc
But now, i wonder since the reading is so low and that was mentioned yesterday, it may be an alternator diode. someone said they had the same as i tested OK at autozone but diode was broken... wired, but hey. How do i test for that?