My apologies, I may have not been clear--when I spoke of shutting off the navigation system I meant the entire system including the music portion of the unit. I do not remember the wire other than recalling a split wire that connects to the chassis and coach batteries. I suspect you have the original Kenwood and the loss of information stored indicates a hard system reset. I was never able to store data in the navigation system for any long periods of time and in hindsight this was a symptom of the Kenwood system eventually failing. To my knowledge it is a single power source for navigation and music systems. I had the toggle shut off in cases where I was boondocking on coach batteries, not using navigation/music, and didn't want to draw from coach batteries. With 440Ah of battery backup, I rarely use the toggle, but wanted the option in case. I hope this answers your question better.
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