Originally Posted by nik
This gauge works, no current = tank at 0, full current = tank full.
nik - not sure you can translate the fact that the needle moves when you power up the gauge into "the gauge works". It could still be faulty.
So to summarise I think what you are saying is:
Sender in empty position 25 Ohms
Sender in full position 240 Ohms
Sender in empty pos. gauge powered on - reads almost full
Sender in full pos. gauge powered on - reads full
gauge power off - reads zero
Where does it read when powered up with sender disconnected?
Where does it read when powered up with sender shorted out?
If the gauge is working these should be FULL and EMPTY respectively. Even if these are correct then I would still say it doesn't garuntee that the range is correct.