brake idiot light will not go out

Switch on parking brake works like a door light switch. Has to be all the way in to turn off light.

Problems in proportioning valve possible are defective switch and a stuck piston assembly. Supposedly, restoring the integrity of the brake system should allow the piston assembly to re-center. Before I would take anything apart for re-build, suggest someone apply pressure on the pedal while another administers a few love taps on the valve to try to free up the piston assembly. Use care, the valve assembly is soft metal. Too much tapping will turn it into junk.