Fuel level sender
 

If I have ascertained that the fuel gauge and the wiring from it to the tank are in good order and working how can I test the sender built into the tank itself? it has two output wires, a green and a black from memory.
How does this sender draw power, create a signal or send?
What kind of metre test can I perform to see if the sender unit is working?

Its a resistance to ground. If you touch the one wire to ground, your needle will peg at over full! Should be able.to test the actual sender with any old meter, preferably an analog so you can watch the sweep and see if bad spots show up.
It will.of.courae.require.you to rmove it from.the car to test it, but if you know wiring and gauge is good and that you have a good ground at the sender, you pretty much have it sussed!