RepairPal Certified shops can diagnose and repair your 2004 BMW 745Li. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
when you say you have tried everything what does that mean ?. do you you have an aigbag lamp on ? do all the controls on the steering wheel work ? These are all connected through a clock spring wich would cause one or all the symtoms including inop horn.