Why is my alternator working?

[i82much]

I noticed my aftermarket voltmeter reads a little low compared to the battery, especially when the fan is on high, so I decided to have a look at the alternator wiring. I don't quite understand, the alternator is unplugged but it seems to hold steady at the battery around 14 volts. Does anyone understand what is going on here?

Truck is a 72 K10, engine is now a 396. I bought it like this, so I can't say much about the history. Where is the main junction usually located on these trucks? I would like to get the wiring correct, have the charge wire going to the main junction through a fusible link and a charging wire from the junction back to the battery with another fusible link.

Thanks!