GPSMap66s and 66st - Changing a Data Box field on the Trip Computer screen to display your current location grid reference - Log into online resource (link online resource - https://gpsonlinecourse.co.uk) > Courses > Garmin - Units > GPSMap66s and 66st > GPSMap66s and 66st -  Changing a Data Box field on the Trip Computer screen to display your current location grid reference