the 2004 Odyssey only has the LATCH tethers in the two center row seats. there are no LATCH tethers in the third row seat
here's what the 2004 Odyssey owners manual has to say about the LATCH system
LATCH (Lower Anchors and Tethers for Children) in the two second row seats. The lower anchors are located between the seat-back
and seat bottom, and are to be used only with a child seat designed for
use with LATCH.
The location of each lower anchor is marked with a small button above
the point. To install a LATCH-compatible child seat:
Move the seat belt buckle or tongue away from the lower
anchors. Make sure there are no objects near the anchors that could
prevent a secure connectionbetween the child seat and anchors.
Place the child seat on the vehicle seat, and attach the seat to the
lower anchors according to the child seat maker’s instructions.
Some LATCH-compatible seats have a rigid-type connection
Other LATCH-compatible seats have a flexible-type connection
Whatever type you have, follow the child seat maker’s instructions
for adjusting or tightening the fit
Make sure the strap is not twisted, then tighten the strap according to
the child seat maker’s instructions.
Push and pull the child seat forward and from side-to-side to
verify that it is secure.
hope that helps