The fuel gauge of this vintage, pre '65 works on 0-30 ohms.
0-1 ohms = E
15 ohms = 1/2
30 ohms = F
The brown wire at the fuse block is for the fuel gauge. From the fuse block the wire leads to the fuel tank sender.
From the fuse block male spade terminal the circuit leads to an in-line connector above the steering column then to the gauge.
Disconnect the brown wire at the fuse block and check resistance of the sender through the wire to ground.
At the terminal of the fuse block, wire disconnected, you can test the gauge operation.
With the terminal grounded and key on, gauge should go to E.
With 15 ohms of added resistance from this terminal to ground, should have 1/2 tank.
With 30 ohms of added resistance from this terminal to ground, gauge should go to F.
