Gas gauge not working. 1966 Barracuda

You need a 12v DC power source, ( battery or power supply)

Hook batt positive to the pin on the circuit board that is 12v in.

Then hook batt negative to the metal housing of the cluster.

Next you need a few resisters ( Amazon eBay etc.) 10 ohms, 5 watt or greater, 23 ohms, and 74 ohms. You can make 23 with 2 x 10 ohm and a 3 ohm in series. Don't get too hung up on the exact resistance values.

Wire one end of the resister/s to the same ground of the cluster housing.

And the other end to the pin that the sender would be attached to.

With 10 ohms the guage should read full scale, with 23 it should read 1/2 scale, and 73 it should read 0 scale ( C or E)