So I am cleaning up my wiring harnesses while I have easy access, and was considering upgrading the charge wire for a future alternator upgrade. But my truck (2000) doesn't match the wiring diagram in the FSM. I only have one heavy-gauge black/blue wire and the ABS relay at the battery, no large white wire as shown in the manual. The black/blue wire is shown, for the starter. Ideas?

2000 Mitsubishi Montero Endeavor, "Katsumi", 138k
1993 Toyota Tercel, backup vehicle, 93k
1989 Isuzu Trooper, "Beniko", R.I.P. at 233k

My 'Genuine Isuzu Parts' decals - for sale