I have a Z1 unit that is a few years old now. Recently it started to act very strangely.....in particular the red arrow icon (which represents the car) begins to rotate very slowly. I have to go into setting and readjust my current location. But even when I do that, it'll take about an hour and the red arrow actually does a complete 180 and the unit thinks I'm going backwards. Again, I've tried to readjust my current location, I've even loaded the default settings, but nothing. Has anyone heard of anything like this? Or have any suggestions on what I could do? The GPS function is useless with this bug.

Thank you

Check your GPS antenna strength and make sure you are locking on to multiple satelites. Your antenna could have gone bad. If GPS signal is good, then reset your 3D calibration settings.