"Why won't my GPS charge?"に関する回答Most likely the usb socket on the back of the unit has come loose (solder pad connections broken away, as item 2 on my report above). Try another cable just in case.
"Why won't my GPS charge?"に関する回答There are two common causes for this, that I have experienced: 1) the GTM25 charging unit had a badly assembled batch, that caused the outer braid of the charging cable (power return/ground) to touch the red +5V power conductor, that was stripped too far back to expose the copper wire, making it intermittently short. That does NOT blow the fuse, because the standard 5V regulator chip in the part that goes in the lighter socket, is designed to check for shorts, and just stop the 5V supply output electronically. The symptom is: the green LED goes out, and the Garmin will then not charge. The fix is to cut open the rubber part of the little “traffic FM receiver” part (the little slim black box), the one furthest away from the USB plug end, and insulate the bare copper wires so they do not touch, then cover the repair in more electrical tape. Ugly but it works. 2) the USB socket inside the Garmin has broken solder contacts. These CAN be soldered back, but you need a really good low-voltage miniature soldering...