Brake warning light & chime, help me diagnose?

[Need For Steve]

For the past several days, less than a week, i've had my Brake warning light pop on with the chime going off each time i've driven my car. I looked in my Owner's Manual for a specific explanation of what it means, but it just says to have the car serviced.

The light has been intermittent. It's not on all the time, and if i stop the car after it comes on, turn the car off and restart, it will sometimes go away for the rest of the drive. I've also observed that in each instance i've seen it, it only comes on *after* i release the brake pedal at a stop, never while i'm actively braking, which makes me think there may be some sort of vacuum issue, perhaps with the booster?

The first time it happened, i came here to read around, and found advice saying to check around the master cylinder for leaks, and to observe the brake fluid level. My fluid level has remained unchanged from my last brake job, and there are no signs of leaking anywhere from the master cylinder's mount, or brake line couplings.

I eliminated the Parking brake as the culprit by unplugging the lead to the master cylinder while the Brake light/chime was on, and they stopped. What exactly is it that the sensor within the master cylinder is measuring when it sets the Brake light off?

[91NinetyEight]

What exactly is it that the sensor within the master cylinder is measuring when it sets the Brake light off?

That's the brake fluid level sensor.

[Jrs3800]

Brake fluid level sensor issues would be my guess as well...

[Need For Steve]

Cool, so i guess that means that my brakes aren't just gonna stop working tomorrow if i drive it? Brake pedal feel hasn't changed, and they function fine.

If that sensor's dead, do i basically have to replace the master cylinder to fix it?

[Jrs3800]

That one I am not sure of.... Keep an eye on it and pay attention to the brake feel...