[Greg Reid]

But, if grounded unplugged without the sending unit plugged in it does not go to full...grounded or not it just lays on full.

I'm not following you here Jay.
With the switch on, grounding the line that goes into the sending unit from the dash takes it to Empty as you said...That works. All you need to do after that is take that same wire off of the ground (just let it hang) and it should go to Full.
If it doesn't, I'd say your gauge is faulty.
By the gauge going to empty when you grounded it, that pretty much shows the wiring is good.