Fuel Gauge

[AdamQ]

Morning All,

I'm after confirmation of a diagnosis regarding a fuel gauge.

The tank is about a quarter full I believe.  With the gauge plugged in, I'm getting 12.7 V on the green terminal, 2.8 V on the green/black sender terminal and earth on the earth terminal, but nothing on the gauge - the needle remains at rest on the left.

When I short the green/black terminal to earth, the needle again remains at rest on the left.  A search on here suggests that under these circumstances, it should read full.

The readings I'm getting suggest to me a faulty gauge as opposed to sender/earth problems - would you agree?

Many thanks,

Adam

[Jonathan Kay]

With the gauge plugged in, I'm getting 12.7 V on the green terminal, 2.8 V on the green/black sender terminal and earth on the earth terminal, but nothing on the gauge - the needle remains at rest on the left.

Is all of that measured at the sender?

Sounds to me as if that's consistent with no connection to the gauge as well as a faulty gauge.

All other instruments OK?

Several possible lines of investigation while I look for the diagram:

1. Check the wires are connected to the gauge.
2. Check the voltage at the gauge end of the sender wire (with it disconnected from the gauge). Does it match the sender end?
3. Ditto resistance on the sender wire (disconnect from gauge and sender and use a length of mains cable to get to both ends).
4. Disconnect all wires from the gauge and put a fused 12V across it and see if it responds. 

Jonathan

[OliverSedlacek]

Definitely sounds like a problem with the gauge.

[AdamQ]

Thanks for the replies.

All my measurements were at the gauge end.  I've tried connecting the green terminal on the gauge directly to a 12 V supply and the other two terminals to earth - not a flicker ...  That seems to confirm that all is not well with the gauge.

Thanks again,

Adam