Actually, B.C. is not taking into account the remaining three bulbs that would provide excitation voltage in the case where the battery (charging) lamp is "blown." But I didn't mention it because the likelihood the charging lamp is burned out is less than slim, because most of the car's life this bulb remains dark.

My next step would be to verify lamp test operates on the bulb failure lamp, the parking brake lamp, and the brake failure lamp. I suspect it does not, if the instrument gauges operate normally, because the red wire to the alternator is interrupted somewhere between. If the other three lamps do pass lamp test (on in KP-II with motor stalled) then maybe the filament fell out of the battery lamp, and we'd need to understand what else happened to prevent the excitation of the alternator field.
--
Art Benstein near Baltimore

Never test the depth of the water with both feet.