All I can see is one red wire coming out that has a white connector on it and that leads to the ignition switch. It seems to me that someone has added some heat shrink tube to the engine side of that connector and I'd almost swear the wire is broken at the end of the heat shrink. May have been an attempt at a fix in the past.
Does the heat shrink tubing hav a bump in it. If the bump is missing I would bet that someone removed the diode, which would explain why it is not charging.