[67 Burb]

Seeing how you have already verified that the sender ohms moves from 0 empty to 90 full, test the gauge on the bench like I have done. I use three 33 Ohm resistors soldered together as in photo. Apply 12V + to the IGN post on the gauge and 12V - to the GROUND post of the gauge.

Attach one end of a wire to the SENDER post on the gauge and attach the other end to the resistors at point "A" on the resistors. Attach a wire to the gauge ground post and touch the other end to points A, 1, 2 and 3 on the resistor string and if the gauge is working properly, it should read A - empty, 1 - 1/3 tank, 2 - 2/3 tank, 3- full tank.