Brake light illuminated

My brake light lit up on dash and will not go off now. I checked the brake fluid level it is fine and brakes seem to function correclty, Park brake is not engaged. any ideas anyone?

I had the same problem on my 01 Sierra. I honestly thought it was the brake fluid level sensor that went out. But after removing the connector of the sensor a couple times, the light came off. It hasn't come up since

bad connection on the brake fluid level sensor. Unplug it, clean the contacts and plug it back in. Of that doesnt work try the same thing with the pressure switch on the proportioning valve. If thats still a no go, try replacing them.