Gentle reminder to all, there are a few Garmin Nuvi around that "does not like" getting power from a standard USB connector that has pin 4 and 5 both shorted to ground and it goes into a "computer connected mode" or USB storage mode. My Nuvi 765 is one and I believe there are a few that have the same problem as well.

Many cable USB headers (or plugs as they are called) have a small plastic contact carrier that holds all the metallic contacts and you solder the wires to the piece before inserting into the USB connector housing. For most of the plugs, there will only be 4 contacts for you to solder on, i.e. 5V, D+, D- and GND, and no connection to pin 4 or pin 4 is default shorted to pin 5.

If you are purchasing a new USB plug to achieve the 17.3k resistor to pin 4, please check that you have access to pin 4 in the plastic contact carrier, i.e. 5 contact and 5 solder pads.