thinking out loud.....
I think the backup lights and/or the brake lights are on an always-hot circuit (not controlled by the ignition switch.)
Could the brake light switch be bad?
Still Original: Tub, Rollbar; Frame; 258 Block; T176; DANA300; Steering; DANA30; AMC20; Drive Shafts; Wheels; Tank; Altenator; Fan; Frt Bumper; Speedo; Heater Box; Spare Carrier; Seat risers
Replaced: Radiator; Valve Cover; Clutch linkage; Taillights; Frt Brake Calipers; Fuel, Tmp, and Oil Pressure Gauges; Exhaust line; Seat Belts; Paint
Mods: Mopar MPI(in progress); 4.0 Al Cylinder Head; OME YJ Suspension; MC Seats; Tub liner; 31" Tires