Terminal block beneath dash?

[Extremeboating]

On the Classic XL/ Pro 165/ and Pro 170 boats there is a terminal block beneath the dash typically close to the dash gunnel side on the right and there are a black 10 gauge wire plugging into it. I've taken a look at the wiring diagrams and there is no indication of the terminal block. Does anyone have any idea what it ties into?

A little background on my boat. I am rewiring the electronics for a triple battery setup, one of the three will be AGM which will be driving the main outboard exclusively and it's tilt and trim/ jack plate functions. One will drive the boat electronics exclusively, which I have a dash mounted dual USB charger retrofitted in place of the 12 volt socket which reads the voltage for that lithium battery. The other battery will be for my troller motor alone which is specifically built as a 24V lithium internally. Three batteries all serving different functions independently.

I am looking to add a dual voltmeter gauge for the main motor battery (and eventually I will wire in the troller as well) so I know what the voltage is. If that block ties into the main motor grounding then that would be a perfect spot to tie my ground into for the voltmeter gauge which I will be adding.

Thanks in advance.

[Extremeboating]

Nevermind. I figured it out. It is a terminal block for the boat electronics on the main engine battery.