Hey guys,
I have a 1991 735il and recently my car has began giving out this fairly loud and annoying "siren". Whenever I plug the battery back in the noise instantly starts, even without ignition.
The noise is coming from the area directly below my right (right hand drive as well so on the drivers side) windscreen wiper and when standing outside next to the car it is to the left of a black sort of cover; and even upon turning the car's ignition totally off, it still blares loudly.
I have to take the battery out for it to stop otherwise it continues until the battery will die.

Anyone have any idea what this could be? I will be sending it into an auto electricion sometime soon, but still it is my only car and the noise is just annoying to drive with.

Thanks!