Warrior on board charger?

[pucknut]

Looking for help with my on board charger. Bought the boat used never had the charger hooked up no manual or instructions. It is a 97 warrior and it looks as though the charger was factory installed, I don’t know however? Do not know the manufacturer either, it is black in color with red lettering. I run a 24 volt trolling motor jumped at the marinco plug. Correct me if I am wrong but I want to set it up as a 12 volt charge? There is a switch on the charger, 12 or 24? It has 3 sets of battery leads main, aux one, and aux two. Correct me if I am wrong but main goes to the cranking bat, aux one goes to troll one aux two goes to troll two. My question is out of the same grommet as the aux one is an additional red wire? Where does this go? It is not the ignition wire as that is separate and I should note there is no such wire coming out of the aux two grommet on the charger?

Any help would be greatly appreciated, thanks in advance.