1990's Sport Craft Avanza 3100 battery charging question

[TominatorNY]

Hi All, I'm working with a mid-1990's (1993 I think?) Sport Craft Avanza 3100 Cruiser. The batteries charge just fine off the motors, but when shore power is attached the 12 v system does not recharge off the 120 v system. There's a breaker on the main panel labelled Battery Charger, and I checked the back of the panel to verify it does have 120 v going to the panel switch. I am thinking maybe the 120 v battery charger is shot, but I can't locate it? Does anyone have any idea where they hid the thing on this model? Or in general, where it is often located? Thanks in advance!!

FYI, this model seems super rare... any info on it would be appreciated. Also love to have some repair manuals if they exist. Thanks!