When I put a 6-volt heater in my 54 which had been converted to 12 volts it would run on high but not on lower settings, it would hardly turn. I don't know if it was 12 volts,s to begin with, late 54 build. I found the heater in a junkyard in 1984, when I was young and ignorant. Now I am old and ignorant. My truck came from southern Indiana and heaters were an option back then.
