HI, I recently had a battery problem. MY wife likes to listen to the radio while she eats her lunch rather than eat in MDs or where ever. My car would not start so she called me to come check it out. When I got there, sure enought, would only turn over slowly, then not at all. While I was waiting for AAA. I was checking out the lights, radio etc. I do not have Nav, but as far as the radio, heater controls, and anything in that area, it would only work intermitenly. Kind of like it had a mind of its own. One minute it would work, next minute DEAD. Since I repalced the battery, everything is fine. Your battery my need replacing, after all, its at least 4 to 5 years old. Maybe older, who knows how long it sat on a shelf before it was installed in your car. :(