The Garmin Nuvi is a well-known GPS that is often used in cars for personal navigation. Though the Garmin comes loaded with maps, it also may need to be updated with additional maps over the life of the product. If you want to update your Garmin, you can do so with an SD card and a USB cable. Properly connect the device to your computer and quickly download updated maps to the memory card.
Insert the Garmin Map Updater DVD-ROM into your computer's disc drive and install the application by following the installation wizard.
Insert the SD card, at least 512MB, into the Garmin.
Connect the Garmin to your computer with a standard USB 2.0 cable.
Open Garmin's "MapInstall" application and select "Removable Disk" from the drop-down menu, then click "Next."
Select the states from the region map for which you wish to update the maps, then follow the onscreen instructions to complete the transfer to the SD card.