Brake bleeding issue

I just completed brake job on my 69 Dart. Upgraded front to disc using a Scarebird setup and kept the rear 10 " drums. Bought a new mc an prop valve for 73 up , and all other parts are new. Went to bleed and fronts are fine,but getting nothing to the rear. I don ' have any wiring hooked up on the car,does the brake switch on the prop valve need power to work?