Lets begin with the nice and simple 3RZ engine starting and charging diagram for an older Tacoma.
When you look at the alternator plug from the little 3RZ engine it has 3 small gauge wires that are red, yellow and white. Then there is a larger gauge white wire that is the main power wire that bolts to a terminal on the alternator and goes directly to the power box's 120amp fuse which links to the battery.