I had something similar happen to me, Try disconnecting the 12v battery neg cable and the little monitoring plug that's right beside it, then charge the 12v battery. after I did that and hooked everything back up, no more messages and no more issues.
If you disconnect the 12v battery (and...
The HVAC runs off the traction battery, which has it's own separate under-hood cooling system. My guess that is what you are hearing, at least that's what I hear when waiting in the pick-up line at G-Baby's school.
I have noticed that if you put it in park and open the door, I'll get a message something to the effect "Do you want the engine to automatically shutoff after 1hr." You have the option to choose "yes" or "no"
My guess would be the inverter system...... as the proximity sensors detect the key, the 12v system comes online to power the curtesy lights etc.... when the 12v system computers fire up so does the inverter waiting for a start command / charging the 12v battery.
According to the installation instructions, they have foam tape that sticks to the outside and clips that fasten under the window frame weather seal and the clips snap into the visor with a couple of pins.
Welcome to the Jungle! Best advise I can give.............. Don't be afraid to try fixing/modifying something yourself........ BUT be smart enough to stop before you can't undo it! ie....... cutting a hole in something to mount a part, then realizing later you don't really like it as you found...
Thought I'd post this, it's a collection of part numbers I've run across. I do not know if the all the retainers/fasteners are interchangeable, but I have ordered many of these and so far they are...
This is what I purchased, I haven't put them on yet. (the 30 min install was for the hood struts, I got the posts confused)
https://www.bamwholesaleparts.com/oem-parts/toyota-visor-set-window-816260840
I have done a fair bit of editing videos in my day, too much work. Plus setting up my own channel...........the Arse holes out there sharp shooting etc........ for me the juice isn't worth the squeeze.
If you go to my build page, you'll see where I tapped into the 12v battery and installed a circuit breaker.
I still have to install a fuse in the run but, the fuse holder I like to use, hasn't arrived yet.
IMO the cargo area isn't lighted very well....... so, I changed it
I purchased 2 of these from Amazon, they have two switches, one for bright white and one for amber, you can have either on or both. I milled off the little bars that are used for a strap around a roll bar for a more streamlined...