1967 Dart no brake lights when lights are on

I replaced the bulbs and no change.
Upon further investigation, it appears there is an issue with the brake lights. I see there is a jumper wire tied into the stop lamp switch wire (white) near the switch. It goes to the tail lamp wire (black) at the bulb. Without it, the brake lights do not come on. Since it is tied into the tail lamp wire, the brake lights do not shine if the tail lights are already on. With the brakes applied there is power from the stop lamp switch and through the connector, the wire then goes up the column. Is there any further diagnostic I can do or can someone tell what the issue is?