Just to clarify, the B/R wire only gets power while cranking the starter. This bypasses the ballast resistor to give a bit of extra spark oomph for starting, but as geezer noted, bypassing the resistor for regular driving can burn something out prematurely.

The B/W wire gets power whenever the key is in the Run and Start positions, and this feeds thru the resistor to power the coil at a reduced voltage for regular driving. I wonder if you may have burned out the ballast resistor at some point? It's just a coil of high-resistance wire inside a ceramic heat shield, so if you don't have a multimeter or test light handy to check it, you can just remove it and inspect to see if that coiled resistance wire is broken. The Herko B108 coil I recommended above comes with a new ballast resistor.