Third Row Tether in Toyota Sienna

[tmlr]

I may need to move either an infant car seat or the Boulevard to the third row for a long car trip. I just noticed the third row (which seats 3 across and is a 60/40 split) only has 2 tethers. I'm trying to juggle lots of luggage, two car seats and my 80 year old aunt in the 2nd and 3rd row of the Sienna. I was thinking of moving one of the kids to the third row so my aunt doesn't have to crawl through to the back and so she doesn't feel "banished" to the back.

Can I install one of the car seats to the third row in the seat without the tether and tether to the middle position? Is it better to move my three year old (Boulevard) or my infant to the third row?

Thanks for any advice you can offer!

[crunchierthanthou]

The infant seat won't need to be tethered. Can you fit it back there with an empty seat next to it? That way someone can sit beside it if the baby needs tended to.

What year is your Sienna?

[tmlr]

Oh, that's right, I forgot the base isn't tethered. I have a 2008 Sienna and am shocked they only included two LATCH and tether points in the third row.

If I decide to put the Boulevard back there, does it need to be tethered, and can I tether it to the middle hook instead of directly in back of the seat if need be?