Hi,
I am sorry but your search may be in vain. There is Fiat eLearn for the x250 model (2006 - 2010) but not for subsequent models. The document is large, and is held as a compressed zip file in the Downloadss section, for which see top of page. Fiat wiring diagrams relate to a function, rather than a specific area. For the alternator you would need diagram E5010 "Starting and Recharging", I have attached a copy which was initially posted by
@Anthony489, and to which he has added some annotations, including colour codes. I doubt that it will be fully applicable, but perhaps help as a guide. For completeness I am also attaching my own colour code translator.