First off, are you using a relay harness with your HIDs? If not you probably should think about using one. Second, I have had this same issue with all my gauges flat-lining and getting the charging system failure warning, amongst a couple others. It was caused by a connection coming loose and making contact with the common grounding plate in the fusebox, shorting out the whole system. I urge you to check any wiring you may have done yourself to ensure its integrity, including the stereo and HIDs.
