Auto parts stores used to keep voltage reducers for just that purpose. You
needed one or more depending on draw. This application would just need one.

Still in the catalog and on the shelf. We sold 134 of them last week.
Who'da thought it?

Borg Warner number is VR1.
1.5 ohm resistance for up to 4 amp load.
Basically a wound-wire resister in a ceramic shell

VR2 is the same thing with a mounting bracket
Any parts store should be able to cross it to their brand.
Cost is about $10
Texas Parts Guy

Thanks Texas Parts Guy. Just proves they made some tough 6 volt cars in the
Good Old Days!

Warren