Amp Gauge Wire Diameter (AWG)
That last part really helped me. Thank you mate!
The wire in question must be AIG 10R, the wire that comes from the grommet onto the ammeter.
So it must be AI circuit, G segment, 10 sae wire, red, I guess
Yes. the battery feed is A1.
According to the diagram the segment through the grommet to the ammeter is a 10 gage wire.
You can compare it to the other wires nearby.
The other wires through the grommet should be the same diameter. Where did each connect is the question?
The one connecting on the ammeter is probably also gage, but these wires in the diagram doesn't match what's on the car.
So
Compare with the standard wiring that is there.
Look at R6 B where it goes into the multiconnector. That's 12 gage
Whether R6C or C13 was on the ammeter stud may not matter as both of them are supposed to be 12 gage as well.
etc.
If, upon removing the insulation, the wire strands and crimp looks, or just needs some cleaning, then cleaning and reinsulating is a good option.
If the wire strands or crimp is poor, then see if the spare harness section you obtained has the same ring terminal and wire.
You may have to splice in a section but with 10 gage wire I think you will be able to create a better wire splice than wire to ring terminal connection.