Low brake fluid

SOURCE: brake warning light

to reset the computer,which stores that info...disconnect the battery for 2 minutes and connect it back up again.

SOURCE: master cylinder brake bleed question

you should first bench blead a new master cyl before installing it on the car.

SOURCE: reset message center window

THIS SHOULD HELP YOU

Turn the ignition to ON without starting the engine. Fully press and release the accelerator pedal three times within five seconds. If the CHG OIL SOON light flashes two times, the system is resetting. Turn the key to OFF, then start the vehicle. If the CHG OIL SOON light comes back on, the system has not reset, repeat the procedure. Follow this procedure to reset the GM Oil Life System using the DE 100 Series Radio®. Turn the ignition to ACC or ON and the radio off. Press and hold the DISP button on the radio for at least five seconds until SETTINGS is displayed. Press the SEEK up or down arrow to scroll through the main menu. Scroll until OIL LIFE appears on the display. Press the PREV or NEXT button to enter the submenu. RESET will be displayed. Press the DISP button to reset. A chime will be heard to verify the new setting and DONE will be displayed for one second. Once the message has been reset, scroll until EXIT appears on the display. Press the DISP button to exit programming. A chime will be heard to verify the exit.

SOURCE: the emergency brake and low brake fluid light stay

you might have to bleed the brake system?? and the vibration is the rotors (slightly warped)

SOURCE: add brake fluid light on but fluid not low

Sometimes the float in the master cylinder gets stuck and you have to carefully work it up and down with a screwdriver or something. The switch might be bad on the float too. If the low fluid switch is telling the system that the master cylinder is low, that will cause the "Brake" light on the dash, to come on too.