Wiring problems of the 2005 Mercedes Benz SL500

My Mercedes Benz has a faulty electrical wiring in the command navigation unit in my Sl500. The vehicle has only 16,385 miles on it, though it is a 2005 model, and has been housed in a high-end garage with no trauma, no damage, and very little wear and tear. I purchased the car used about 6 weeks ago. Within the last 3 weeks the unit has gone from working intermittently to not working at all, simply providing a screen message: system unavailable. On March 5, 2012 I took my sl 500 the authorized dealer here, and contacted the service manager . After having my vehicle out of commission for two days, I read the diagnosis/repair report and was told this was not an error by me or the previous owner but something that happened somewhere in the manufacturing process, probably on the assembly line, as the sound amplifier had an internal electrical fault. Additionally, I have been to two independent Mercedes Benz dealers and they could not fix the problem. I've also learned that I cannot simply replace the stereo with a working model from any electrical store (like best buy or car stereo guys). It is my understanding that to replace the command unit would cost several thousand dollars. It is my belief that while the car is not within a typical five or six year warranty period (I just missed that period) it is clearly a car that has been well taken care of, barely driven, properly housed, and maintained. Given the findings from your authorized technicians, it seems that this is a problem that came with the car that would have surfaced at some point. Lucky me that it is surfacing now. I am hoping that the national highway traffic safety administration will contact mercedes about this faulty command unit. There are many other mercedes owners who have and are experiencing this electrical nightmare.