There is nothing to experiment with. 6 volt heater switch WITH single quad lead 5 watt resistor built in right? Maybe you don't have an original switch then. The original switch has the resistors on it, a fuse holder and if you put your 12-6v drop before the switch, life is good other than the hot drop resistor. This isnt an AC motor so there isnt any mystery, just two single ohm resistors in series, (one after the other) with the junction between the two being your medium pickoff. If the resistor is broken or has been deteriorated, for 6 volts, use .8 ohm 5 watt resistors like GM did. For 12v, use 1 ohm 10 watt resistors. Use NO resistors if your switch is good because they are already on the switch!
