Yea. It was a lot of info for you to absorb in one evening.
Take some time and go back through it all and it will start to make sense. Make your own drawings and sketches. Whatever it takes for you to learn. For me its drawing stuff out or at least tracing it.
Seperate the stuff from last night into two categories. Stuff related to supplying power (main circuits and connections). Stuff related to the gage operation.
For the gages, look at the Master Tech before diving back into the thread.
I is input. I don't know if its from the Ignition Run circuit or the Switched Accessory circuit in your car. But either way it is powered with the key on.
A is the IVR output. So I should connect to A. So the heating coil is open.
S is to the fuel sender. A should connect to S with about 20 ohms resistance
That's about all I can offer now. FABO will freeze my desktop - as it did last night - and I can't have that happening.