2024 Toyota Sienna XSE has no heat and the dealer is confusing

[ChilliChamp]

My 2024 Toyota Sienna XSE hybrid has had no heat for over a week. The dealership initially couldn't figure it out, then suspected and replaced the thermostat (after a delay due to parts shortage), but this didn't fix the issue.
The mechanic is still stumped, so I contacted Toyota directly, who stated it's not a known issue in their database but will contact the dealer to help expedite.
I later learned the dealership's hands are tied regarding warranty repairs without direct authorization from Toyota engineering, which explains the delays. Communication with the dealership has since improved, they now communicate regularly with me. It's better, but idk when they finish repairing

 

[StarBoy11]

It's sad to see something like this on a new car. Did the dealer mentioned what the problem is or they're still investigating?

 

[PitStopPro]

I dealt with a similar headache last year when a friend got a brand-new hybrid SUV. It wasn't producing any heat, and the dealer was totally puzzled. We ended up going back and forth with the manufacturer for a while. It took weeks, but eventually, they figured out it was a control valve problem they hadn't encountered before. I hope yours has been resolved by now