[JSeery]

The tail lights and brake lights should be two totally separate circuits. The brake lights, via the brake light switch should be "hot" all the time, so brake lights whenever the switch is closed. The tail light are powered through the lighting control switch. If both are out I would think it would have to be a connection that includes both or a ground issue at the tail lights themselves.

The stop lights are (at least should be) wired directly from the CB terminal to the stop light switch to the brake lights.

The tail lights would be directly from the CB terminal to the light control switch to the tail lights. The license plate light should also come on with the tail lights. The clock light and instrument lights are also on the same light switch terminal as the tail lights.