I didn't see a response back here on this page, but want to send the following information before I take a short break.
You can get Mexico maps at the following link - in one of two forms - which are either by "download" or "Pre-programmed" onto an SD card.
If you have more than a week or two before you travel, I would recommend getting the SD card - as it is VERY EASY to installed (it is a matter of plugging it in and verifying that the maps are enabled).
Click Here --> https://buy.garmin.com/en-US/US/p/11427/pn/010-10755-00
Another note: IF using the "downloaded" maps, MAKE SURE your device is "registered", and that the email address used during the purchase of the Mexico maps is the same as when you registered the device.
Once purchased, the maps should appear in the Garmin Express program for download.
I hope this helps. Please let me know what you find or if you have any more questions about your device or the maps.
If this has helped answer your question(s), please take a moment to rate MY service level (5-star is my goal) so that I get credit for my time helping you with this question.
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Thanks, ***** *****