OK, my bad on the 500mv, I don't know what I did but that wire has 12.55v with the ignition on.

However pins 3 and 4 do not show any continuity on my meter whether the switch is activated or not.
-Is this a test that I should do with the switch plugged in? (I have been doing all of my tests on either the harness or switch when I have had them disconnected.)

-If it is a faulty light, is there a way to repair it?
-Would this maybe be enough for the self diagnostic mode to not activate?
-Is a light fault enough to trigger a sub tank fault light in the dash?
-When the dash light gets activated does it suspend the system from attempting to work?

The car is in Brisbane until next Wednesday so I might order a new switch tomorrow in the hope that that will fix it.

Sorry for all the questions, but you guys are geniuses, a whole heap more helpful than the bloke I had look at it in Isa he told us that "it is what it is, carry jerry cans"

Thanks for the help