It's behind the plastic panel between the Steering Column and the hood release handle, a little closer to the hood release. It is at the bottom edge of the panel facing down. You can feel it with your hand, but you will need a mirror, and maybe a flashlight, to see it, or get on your back and look up. After you look at it in order to orient the ODBC plug correctly, you can connect to it easily with the ODBC connector just by touch and feel.
The 2004 Hyundai Elantra OBD 2 port is on lower edge of dash between steering column & hood release
The 2003 Hyundai Elantra OBD 2 port is on lower edge of dash between steering column & hood release
The 2005 Hyundai Elantra OBD 2 port is on lower left dash between steering column & hood release
The 2005 Hyundai Elantra OBD 2 port is on lower left dash between steering column & hood release
The 2007 Kia Optima OBD 2 port is right under driver side instrument panel near center console
The OBD connector is under the dash on the driver side.
The 2007 Toyota Rav4 OBD 2 port is on lower edge of dash, right of hood release
The 2007 Mercedes CLS OBD 2 port is under driver side dash next to hood release
The 2007 Toyota Tacoma OBD 2 port is on lower edge of dash in cavity, next to kick panel
The 2007 Nissan Maxima OBD 2 port is under driver side dash left of steering column
2007 Honda Accord OBD 2 port is under driver side dash next to kick panel
The 2007 Honda Civic OBD 2 port is under driver side dash next to center console