3. The "Interconnect Valve Switch" (on the HYDRAULIC SYSTEM PANEL) isn't operational.Talking about this thing, No.12
Apart from the fact that I think that the labels are hard to read there, I find this switch to cause no change at all. It's not working.
See here
When positioned to OFF, "Aux" should be isolated from "Utility" and from all other systems (which can be connected via the other switch positions later).
But, as you see here, "Brake" is already pressurized although not connected and not driven by the engine pumps (because engines and pumps are off).
When positioned to BRAKE those Aux pumps can pressurize the "Brake" system which does happen but shows no difference to the OFF position of that switch.
The switch therefor isn't operational. See here, no difference to the above picture except the switch position.
Last position of that switch, the SYSTEM position. Switching to it means that the Aux pumps can pressurize the "Utility" system. Therefor the "UT" gauge should read pressure but it actually shows no/low pressure.
So you can't pressurize the utility system without the engine pumps running (which of course requires the engines to be running too and would enrage every load personal together with raising the fuel bill).
The switch, again, has no function here and seems to be stuck to interconnecting the brake system, regardless of its position.