95 cavalier buzzing noise in dash

i just bought a 95 cavalier and it has a buzzing noise in dash once i turn the key (before the engine is started) and then when it is started it continues to buzz. its pretty loud and annoying i would like any suggestions on what it could be. i was thinking maybe the heater or something?

i just bought a 95 cavalier and it has a buzzing noise in dash once i turn the key (before the engine is started) and then when it is started it continues to buzz. its pretty loud and annoying i would like any suggestions on what it could be. i was thinking maybe the heater or something? A shot in the dark here but I had a `91 sunbird that would "buzz" ,it turned out to be the controls or relay for rear window defroster. Never did get into it tho, just flipped the switch a couple of times and it would quit. Try pulling the fuse for it see if it stops . if it does yuo`ll know where to look...........LOL