LOL!
The ballast resistor was like a $ 4 part, located on the fender under the hood, and you are right, the MOPAR vehicle was dead if it went bad.
Once you knew about it, you could make a dead vehicle start like magic by replacing it.
Had a ceramic one on a ‘78 Dodge pickup that gave us fits when the vehicle was only one year old.
A lot of mechanics did not even know about it.
Your post brought back a flood of frustrating memories.
I remember those. If it went bad the engine would start, but die as soon as you disengaged the starter. The ignition coil was actually for a 6V system, and the ballast resistor dropped the voltage to the coil so you didn’t burn it up. There was a second wire off the starter circuit that bypassed the resistor and gave it the full 12V to insure you got a good spark while it was starting.
Most of us mechanics that knew about that damned ballast resistor ALWAYS kept a spare in the glove box.