What you did was jammed the piston to the back (rear brakes), when you blow air into it, with the other side open (line off). and it is shutting off the flow to the rears. Normally it would self recenter it's self, when you open (release) the pressure to the side that works. Try this, remove the terminal switch, releasing the pressure to the fronts, and tapping on it's sides and see if it's just stuck lightly. Find the light brown (tan) wire hanging around and rehook it to the switch. Light on dash should be off when centered.

Or you can try to have someone open a front bleeder, and then jam on the brake peddle, (First remove the terminal switch) but don't let up on it or you'll get air in and have to re-bleed the fronts. Try it a couple of times, checking after each time to see if you have flow to the rears.

If you hook it up the way you say, the rears may always lock up.

Pat