Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
The problem you describe may be the battery, or it might possibly be something else.
How old is the Garmin Nuvi in question ? this matters, re battery replacement.
Also, what model is it? which also matters.
Please let me know, by using the Reply To Expert function, and I will advise you.
At 16 months, you may as well try replacing the battery - it is out of warranty after all - rather than send it to Garmin for repair.
However, to determine the battery to replace, we will need to know the model #. It may be under the battery hatch... in which case, just getting the numbers off the battery, specifically the maker and model # of the battery and its V. or Volts rating, would be best.
Are you done with this question? if so a rating for my work would be appreciated.
(Or do you just need a pause? if so that's fine.)
I know the tool type you mention: it is called a Torx.
I own a set of Torx drivers. But it cost me something. They are specialized tools, indeed.
Perhaps it would be more economical for you to send te device to Garmin; The choice is yours to make and all I can do is advise you on it.
Is there really no way (label, sales slip, credit card records) to tell what model the Garmin device in question is?
Thanks for your remarks about giving my service an A... but I'm not done trying yet.