a stock setup doesn't have the generator output to the ballast resistor, the voltage at the resistor should be battery voltage [via the ignition sw], and the resistor should drop that to around 8V .... sounds like you may have an internally resisted coil that doesn't require a ballast resistor

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