Brake Warning Idiot Light

[ChallengerHK]

Weirdness. My brake warning light stays on. I assumed it was the emer brake switch, but it appears to test good. Today I put new front bearings in, and I had to compress one caliper piston to get the caliper back on. After that, the brake warning light was off for about a mile. Can anybody clue me in about what's going on here?

[Chryco Psycho]

in the proportioning valve there is a switch , if the pressure in the front & rear system are equal  the switch will stay centered & the light will stay off , if the front & rear systems do not have equal pressure the switch will move to the system with the lower pressure & turn the light on . By compressing the caliper it must have move the switch back into the center position & turned the ligth off , the front system must have the lower pressure if the light came back on so if there are no leaks you could have a bad master cylinder

[ChallengerHK]

Thanks, CP.