Can anybody give me a brief synopsys of the fuel gauge gauge wiring?
I am trying to bench test my sender unit on a good gauge.
Is it like this image?http://img.villagephotos.com/p/2004-2/638601/Gauge.JPG

Yes, it is just like your image. Congratulations, for a very fine effort using "paint". I have never been able to do as well as you have with the paint program.
The voltage travels first to the gauge, then, grounds through the sender. The sender has a variable resistor to indicate full to empty, and analog in between. The voltage going through the gauge first, limits how much current can go to the gas tank, a very important consideration, 'cause too much current (heat) could start a fire.

But you must run a ground from - on battery to metal on sending unit to bench test.