My S-10 is having elecrical issues

My S-10 is having elecrical issues. When I press the brake pedal the parking lights come on no brake lights, and the buzzer that lets you know your headlights are on sounds. Also the digital clock on the stereo gets dim and blinks on and off when I turn on the turn signal. I know this is a short of some kind but I've checked the brake switch by bypassing it with a wire thats not the problem. I've also checked all the bulbs for shorts all are good. What could this be?