@Thomlodz
Many Garmin devices are very prone to their USB socket suffering physical damage. For instance: (i) the socket's internal pins may be bent or broken; or (ii) its soldered connections to the PCB may be damaged. Easily corrected by repairing/replacing the socket in the first instance and by simply reflowing the solder in the second instance. Often with those particular problems the device can be charged but there's no USB recognition of the device by computer, or vice versa. Sometimes it's as you've experienced and there's neither function. There can also be a failure of integral components on the PCB resulting in such symptoms and that's usually the case once the USB socket and cable used have been proved serviceable.