Wiring question

[R.O.B.]

If you look at "A", what does that wire do? And what size fuse should it use? (mines missing)



Same for "B", what does it do and what size fuse should it use? (again, fuse missing)



And last but not least, can I just connect wire A into the same place where wire B connects, inline from the alternator to the battery? This would help clean up the wire mess that I have.



Thanks,

Rob