A Garmin GPS device that won't start is either suffering from problems with the battery or issues with the internal hard disk. When troubleshooting the Garmin GPS, you might need to determine if the battery, power outlet or battery cable is the problem. A Garmin GPS can be charged in a multitude of different power outlets, which makes it easy to assess whether or not it's the power outlet or charging cable. To assess a hard disk problem, the device will need to be reset.
Reset the Garmin GPS device. Hold the "Power" button on the top of the GPS down until the device resets itself.
Charge the Garmin GPS device properly. the Garmin must be charged in an environment no colder than 32° Fahrenheit, and no warmer than 113° Fahrenheit. Also ensure that the Garmin is not placed in direct sunlight when charging. Try charging the GPS using a different power outlet to make sure the power outlet that is currently being used is not the problem. If you typically charge the Garmin in the car, try connecting it to the computer with the USB cable and allowing it to charge from there.
Replace the fuse on the charger. If the charging cable is the problem, purchase a new charging cable or replace the fuse. To replace the fuse, unscrew the end piece or cap at the very end of the charging cable. Remove the end piece along with the silver tip underneath it with your hands. Pull out the fuse with your hands. Replace the fuse with a new 1A fast-blow fuse, reattach the silver tip to the fuse and screw back the end piece.