Hello,
the nuvi charged when you plugged to the car charger.
Boot BLK : B0972-00 5.80 Nuvi Boot block software Pass
Passes almost everything beside the last rows:
UKCyclopsSample.gpi
BeluxCvcyclopsSample.gpi
etc when I got an Error

When you plugged to the cable in the same time you`re in the testing mode screen you can see:
I Limit USB 1A
USB device USB type-B
USB ID volts 2.25V
I Dont know if that helps somehow....