On my 03, and likely all, the positive lead goes from battery to alternator, to something further back on the chassis.

what is that? I first thought external regulator but our cars are internally regulated alts?

 

Anyone?

 

Where on the chassis? Unless you mean the engine which would be the starter.

 

Its wired to the alt, on the chassis directly behind it maybe 2 feet? Def no starter.

 

Here:
http://www.nicoclub.com/FSM/G35/Sedan/2003/
Grab yourself the SC and maybe the PG books and you can read up on the Charging and Power circuits (with big thanks to the NICO Club).

 

From what I can tell on these terrible pictures, its a starter motor?

 

Yes, that's probably what you're looking at. The largest cable from the battery + terminal goes directly to the starter. But the starter takes so much juice to crank that it needs to be switched on by the solenoid which is kind of behind it, closer to the fire-wall. That gets energized and hammers together the really large switch contacts to connect the high-amperage cranking power. Makes sense?

 

Yea, when someone originally said it was the starter, I was like uhh thats no starter, but a solenoid makes sense. Waitimg for my new 220amp alt now

 

^Technically the starter and the solenoid are considered a single unit.