'65 Dart No brake lights. Brake light switch failure?

At least you don't have a Ford Cougar. It was an upscale Mustang, with one feature being multiple rear turn signals bulbs which flashed in sequence to form a moving light. A complicated setup for the 1960's with multiple relays and timers, requiring much skill to restore them today. Might have been tricky hooking up a trailer connector, though few Cougars would tow. Even trickier was a GM convertible with hardtop which stored the top in the trunk, all automated via many relays.