65amp wiring/trouble shooting

Now the confusion starts: There's a split on the positive battery cable which isn't showed on the chart. The A1A-10R is correct, but there's a bigger one going on the starter, but that must be standard, obviously. I'm just confused why this isn't on the chart.
Mark,
My drawing is a simplification focusing only on the main circuits for powering the car.

The service manual drawings show all of the wires. Do you have a copy?

Like this ?
1689977329570.png

it shows the battery connectors as CE27
The positive has as a 6 ga wire to the starter and the 10 ga wire to the starter relay.
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