My '48 GMC has been converted to 12V and the rheostat function on the old headlight switch doesn't work. Some of the old Ark-Les heater switches use low-medium-high settings while others incorporate a rheostat and I'd like to run my dash lights through one of them. Since most of these switches were used in 6V applications I'm wondering if they will work in my 12V truck. Any experiences?

Thanks, Jim