the gauges have -5 volts to them to make them read the ohms, not to the senders
.
See the attached schematic as it better explains how a
basic fuel gauge circuit works. For the Mopar systems, the 5V is supplied by the voltage limiter device is found on the gauge cluster PCB or sometimes built into the fuel gauge of most Mopars in the 60s/70s/80s.
Just my $0.02...
Looking closely at your diagram there are no wires, voltage supply, hook to the indicator needle, correct
That being so the coils read the ohms from the sender and pull the needle towards them when they have the highest or lowest ohms to make them work like a magnet, correct
As already posted any voltage sent into the gas tank sender could and would cause an explosion in the tank when the ignition key was turned on activating the sender when jumping across the parts to make the connection to read it, correct
Ohms don't spark
