fuel gauge sender, Bench testing Options

[80cap]

Before I install my fuel tank is there a way to bench test the fuel level sending unit?
Thanks Brian

[Retroracer]

So that would point to either wiring or gauge being incorrect. 0 - 70 ohms is about right for the sender. Couple of things to check:

1) with the sender disconnected, take off the sender wire at the gauge. Measure the resistance to GND on the wiring. There should be none measurable (high impedance), BUT if the wiring has a resistive short to GND, then that would throw the "empty" reading off.

2) make sure the +12V feed to the gauge is fused, switched 12V - not via anything random or resistive (like a backlight bulb). It is always surprising how creative PO's can get with wiring "fixes"....

3) make sure the combo gauge has a GND connection to chassis (so it isn't trying to GND itself through the sender)

4) if the sender is disconnected from the gauge, with power on, does it read "empty"? If you then short the sender terminal to GND does it read "full"? If not your gauge is broken...

Hope this helps,

- Tony

PS. The obvious question: is your petrol tank half full? ;-)