Originally Posted by ttphilip
Was it working properly recently or have either gauge or sender or their wiring been replaced since working correctly?
If the gauge and sender ohms standard were not matched ( USA standard with Euro/metric standard gauge/sender combination) the gauge could be reading Empty when full.
They both have to be the same standard, and working, for the gauge to read correctly.
You can check the gauge : if it is USA and good it should read Empty or below if the sender wire is removed from the gauge S terminal with power (and good ground to the gauge, and it should peg Full if the Gauge S terminal is jumped to good negative ground. If the opposite gauge progression happens, it is likely a Euro/metric gauge.
Pull & test the sender in Empty to Full position if it is the float-type.
If USA,on your multitester it should show ~ 240 ohms at Empty and down to ~ 33 ohms at Full position.
If it's Euro it should read low resitance around 10 ohms at Empty and just up to ~ 180 ohms at Full.
A matched Euro gauge & sender could, for example, display pegged-Empty if the sender wire was chafed & shorted to engine or other ground. USA matched set would read Empty if the sender wire circuit was open, ...disconnected but not grounded out.