Fuel Pressure Switch Question

[nnyerges]

I am organizing and arranging all the wiring of my boat twin inboard diesel engines instrument panel and I have little doubt about the switched +12VDC power of the instruments.

They are currently connected as shown in the diagram INS1.PNG. Obviously, the “fuel pressure switch” is only to feed the instruments main +12Vdc. The questions are:

1. Is that “fuel pressure switch” is only installed, to feed the instruments?
2. Is not enough to power the instruments form the +12Vdc of the ING.SW (See diagram INS2.PNG)?
3. Maybe I have mistaken identified the complete route of the “fuel pressure switch”, but its goes somewhere else into the engine?

Thanks in advance

Note: The diagrams show the starboard side only. The port side is identical.