IGN warning light

[Lynn Eades]

Andrew, The bulb in the warning light only has to cope with about 14 volts, max.(in a 12 volt system) Yes to change from 6 to 12 volts, those things need to happen. A volt meter only indicates the voltage, an ammeter indicates current flow.
There are three elements: Voltage, Current and resistance. (Amps, Volts, and Ohms) each affects the others.

Think of it like water.
Pressure comes from the head (height of the water tank)= Voltage.
Current (flow) is dictated (limited) by the diameter of the pipe, and limited by the restriction as in a tap. (or as in the resistance filament of a bulb)

Mike, you might well be right about some systems. I don't know.
However in the case of the carriers I believe the ignition warning lights have 6 volt bulbs and would require a 12 volt bulb if the carrier was converted to 12 volt.