No Brake lights/flashers/signals 75 Dart

I don't believe the brake switch would have any power unless the pedal is depressed.
I'm also assuming you have checked the fuses, and that you are doing this with the key ON!
I'd probably start looking for a bad ground (either at the fuse box, or going to the tail lights and blinkers) . I had a bad plug kill both my brake lights. There's also also a little flasher unit in the fuse box for the blinkers...but if your brake lights are dead too...I'd start elsewhere. Reverse lights work? Those are usually on the neutral SS, if it's an auto.