Yesterday I went to start my car and it was pretty much dead. I jumped it and noticed a buzzing sound that sounded like it was coming form under the dash and everytime I hit the brake the radio would die for a second then come back on. And the needles for the tach and the voltage meter are a little shakey. I dont have any special sound system and havent done anything lately that would affect the electrical system.

 

did you check the alternator? that might be the reason why the voltage meter jumps around. Not sure about the buzz under the dash. If your alternator is dead, battery don't get charge, so there's not enough juice in it to light the brakes, radio, and the engine.

 

bad alt, or charging system