The cars manufacturer original stereos once become malfunt would require contacting an auto electrician dealership that may have several restoration methods to revive the condition. Once evaluated would decide to repair the fault where options of replacing with an alternate compartment structures are mandible. Local BMW dealerships that have technical departments would be most appropriate mean of resolving the conditions. Alternately, contact auto electronic technician would evaluate to determine the most compatible compartments and processes required to achieve repairs. Usually a malfunction part is replaced with new functioning compartments compatible with the manufacturers default. Unless malfunction parts were unattainable would an entire structure of kits most suitable for the restoration be means to consider.