unfortunately the 40's wiring diagrams don't have that info, but you can judge by this 1950 one, which should be close to the same in terms of layout and is 6V

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics