Fuel Gauge 1971

[JDININO57]

The fuel gauge on my 1971 is acting odd.

With the key off, the gauge points just above empty.
When I turn the key to the on position, the needle moves to the left and points to empty.

When I disconnect the brown wire from the sending unit, it moves rapidly to the right and stops at the 3 o'clock position.

When re connecting the brown wire to the sending unit, the needle moved rapidly to the empty position.

It is a replacement sending unit.
The float is intact.
There are 10 gallons of gas so it should read roughly 1/2 full.
I measured the resistance of the sending unit and set the reading to OER with no response.

The resistance of the sending unit is near zero when in the full position.
There is measurable resistance when in the empty position.

Voltage at the sending unit is 10.4V

Any experience is appreciated