Thanks for your input!
Your post has genereated many questions in my mind...
If there are 'X' number of seatbelt hardpoints, why wouldn't the dealer (or in this case, me) simply connect them? How hard could it be?
Think of all the substantially more complex things dealers do on a day-to-day basis.
A brake system, for instance, contains all sorts of pins, clips, bolts, hydraulic lines, sensors, etc.
The potential for catastrophic failure - and the accompanying exposure to liability - are magnatudes higher for any brake job versus, say, a rear seat install.
Taken further, that new brake job is going to be used several times a minute (in the drive home from the dealer). That seat will get used ten times a year.
Changing to 2" larger diameter wheels alters the factory-engineered handling characteristics of any car or SUV - yet, dealers commonly do this for customers.
So, if a dealer refuses to add my third seat, shouldn't they also stop doing all "dealer installed items"? Or other options 'left out' at the factory, yet desired by customers?
If the 3rd seat could be substituted by build order during assembly at the factory, why not now?
The factory engineered mounting points exist in all (2004-up) Highlander bodies. The hardware,belts & the seat itself all exist as replacement parts. These parts should be available new at a dealer or used at a boneyard.
It can't be that difficult. Plus, I'll just do it myself.
I would be especially interested to hear from someone who has actually done this retrofit. Particularly if they twisted the bolts themselves.
Maybe I'll turn out to be the pioneer