The Brake light and noise comes on when I have the E-brake on and try to start driving the car, I'm not sure it serves any more function then to let you know the E-brake is on, I could be wrong. I know you said you don't think it is the the E-brake but I would try fooling around with it and see what happens. If that is the case, it should not make any noise when in park, only when you put it in drive.