Fuel gauge swap & wiring diagram question

[fredintoon]

jmailley posts about swapping a Special tank onto his Standard.
I replied mentioning the differences in the fuel level senders and that I thought the Standard sender would not fit into the Special tank.
Then I thought, perhaps the innards of the Special's round tach c/w it's little red light could perhaps be installed in the Standard's square tach body? Or not? Anyone know?
Next I looked at the wiring diagrams in my Clymers. SG/SH diagram shows the red light powered when the thermistor is exposed to the air and grounds it.
The G/H diagram shows the gauge and the sender both with one side grounded and their other sides joined together. This can't be right???

[randy]

The G/H diagram shows the gauge and the sender both with one side grounded and their other sides joined together. This can't be right???

That is right, Fred. The E/F/G/H gauge gets powered from the brown circuit, then it's wired to the sender. The sender is a rheostat with one end grounded. At the gauge there is a regulator that limits the voltage to 7VDC.

For the E/F/G/H the simple route is +12v----regulator----gauge---sender---ground.

I don't know jack about the specials.

[fredintoon]

That is right, Fred. The E/F/G/H gauge gets powered from the brown circuit, then it's wired to the sender. The sender is a rheostat with one end grounded. At the gauge there is a regulator that limits the voltage to 7VDC. - - -

Hi Randy,
OK, that makes sense. It's that my Clymer's diagrams show the E /F gauge with 3 wires; Dg, W & T which may well be correct but the G/H gauge is shown with only 2 wires, Dg that goes to the sender rheostat and B that goes to ground. The second sender rheostat wire is also B, also ground.