Fuel tank sender wire

[garyclio52]

Hi guys
Fitting a race dash to the Clio 172
Worked out all the wires other than

Fuel sender wire

Iv identified 2 of the 4

Earth black
Live thick yellow / cream

Then there's 2

Purple
And
Cream/yellow

The purple I think is fuel gauge

But cannot get any ohms full or empty

Any help will be great
Thanks gary