I seem to remember that a good approach for voltage control in a gas gauge circuit is to put a Zener diode in-line. The diode will 'cap' the voltage at 6 volts (or what ever value you have purchased) and register the voltage changes as sent from the sender. I did it on a '47 Chevy truck. The gauge needs to receive the changes not just a steady 6 volts. This tidbit is from an old street Rodder magazine.--- Frump
