the past couple mornings on my way to work my brake light has been on. it will stay on for about 15-20 min then go off. it's not the brake fluid because i already checked that, anyone have an idea what it could be?

 

ebrake cable, excessivly worn down pads. a possibility.

 

Brake light on for the first few minutes of driving and then off again is almost always a sign of low brake fluid.

Are you sure you checked your brake fluid and not your blinker fluid?