CNIXZGO

I have a weird noise coming from under the emergency brake area when i idle. I have a 78 280z. The Emergency brake works fine, then when i take it off, the Brake light stays on, i put it in drive and it goes off, then when i stop and idle, a weird hum comes from under the e-brake area and the light goes back on. then when i accelerate, the humming goes away and the light goes out and everything is fine. any suggestions on what it could be? I checked all brake fluids and it seems to be fine.