Nehrich

So I just bought on 04 automatic roadster, and I just realized that the parking brake does not turn on the dash "brake" light. The light comes onwhen starting the car, but that is the only time it will come on. I was even installing a new stereo and I connected the wire from the stereo harness to the parking brake wire, and the stereo is getting a signal either, so I can't watch videos or hook up my bluetooth. Any ideas on why it is not turning the light on? Thanks.