No power anywhere, no lights, won't turn over, fully charged battery 2008 Highlander

Well I'm no expert on that model but it sounds like you blew a master fuse or breaker somewhere. Locate the fuse panel and see if you have if you have a blown high amperage fuse.

Thank you. We also have a 2013 Highlander, so I swapped batteries. I did get some dashboard lights, but car would not start or turn over. I could hear a faint high pitched whine under the hood. Disconnected the battery and returned it to our 2013. I don't understand this! Toyota just called back and said they believe it's the starter, bring it in. Ha! Something like you say, is blocking power.

If you do happen to pull the starter off you can take it in to almost any local parts house ( Oreilly ,etc,) and they will check the starter for free.

Hello again all. So I decided to buy a new Toyota Tru Start battery and try it. After installing it, I had only headlights, a few lights on the dash, but no start, just like the good battery from my wife's 2013 Highlander battery. I still heard the faint whine from within the engine compartment. After 3 minutes or so, the electronic system (according to the dash screen) did a system check scan, and then power was restored to the start/stop ignition button. Everything is good now. Weird. The 'bad' battery showed fully charged on my trickle charger, but for some reason, it was not good enough. Thanks for all your help.