84 733i. I disconnected my battery the other day and now when I start the car there is this wierd horn going off in the dash. I don't know if that is the problem or what caused it. I never knew there was such a horn in the dash! It has no security system on it. Is this some kind of warning sound for overheating? It sounds like the horn on an outboard when the water pump shuts down. Any ideas would be a major help. Thanks Taylor