[evVanagon]

No resistance across the D and N side of both P104 and P1517 components. They're both connected together somehow as well.

These are only connected to Pin 21 and 23 of CN100. Out of those two pins, Pin 23 only has a wire back to connector F23 pin 18. Red/black stripe which is +12V Battery.
Since the two terminals have continuity Pin 23 of CN100 is also connected to D102 (to the top right of P104).

Here's a picture of the otherside:

 

[evVanagon]

On the backside of the board there is another component P105. Has the markings: some X symbol with 150F and 24V.

These P components are referring to fuses. https://www.allaboutcircuits.com/electronic-components/datasheet/MINISMDC150F/24-2--TE-Connectivity/
P105 is a ressettable fuse with specs below.