Broadcasting live from sunny Tampa, Florida...
my Garmin GPS indeed has a USB port, I i noticed that when i plug in the GPS it powered up 7 charged the battery...
taking a chance on bricking my GPS, i bought a generic USB to car lighter, cell phone adapter. it worked.
ii just velcroed my GPS between the fafing & windshield.
Mondo Cool!
i would think that brown & yellow are 5v + & -...
--Lucky