So from what I understand this warning light is supposed to come on when the brake system fails or the rear pads are too worn or when the handbrake is on. When I insert a bulb in at the gas gauge, I get the light and a awful buzz coming from the dash. Same result with parking brake on or off. My brakes work great, and my rear pads are plenty thick from visual inspection. My guess is that a switch is stuck closed somewhere in the circuit. Where should I be looking?

The only 2 things that cayuse the light to come on are the EM brake or the Master cylinder. To find out which is causing the problem on the Master cylinder there is a switch with one or two wires on it ( located on MC under car) pull those wires off and see if that stops it. If it does you will have to reset the switch if equipped by
pressing the button between the two terminals. If it still stays on you have to check the wiring or the switch on the EM brake. Most likely cause is the wire is grounded to the EM switch or the switch is bad.