Air recirculation setting sets itself

[Aptos Driver]

Often when I start up my RAV4, the air recirculation light on the electronic climate control display comes on even though the climate control system is turned off. Does anybody have an idea why this is happening?

[kavatski]

I haven't quite figured out the logic behind it myself, but it's normal. Having had the vehicle in all seasons now I've seen that it has something to do with inside vs. outside temperature, since it only occurs in warmer weather. At first I thought that maybe when it's warmer outside than inside, it thinks it's helping you out by turning on recirc, but it still seems to do it at times when I'm positive it's warmer inside than out (when it's been sitting in the sun on a hot day, for example). The climate control system has a neural network "brain" that's supposed to be better at controlling temperature and airflow to suit the way humans feel, but the recirc behaviour has me stumped.

[Aptos Driver]

Well, I'm glad to know that it's not just my car that's doing it.

[kavatski]

I'm in the habit now of reaching over and touching it off every time I start up and it comes on by itself. I wish I knew what it was doing it for, since it obviously thinks it's smarter than I am...

[kavatski]

Played with it a bit this morning. The indicated outside temperature was 25C. Interior temperature set to 22C. Recirc mode came on automatically. Raising the set interior temp resulted in recirc turning off when the set temp got to 25C, same as the outside temp. I then lowered the set temp again, and recirc turned back on at 23C. So at least in this case, it turns recirc on by itself because it doesn't want to blow fresh air at you that's warmer than your selected interior temperature, even if you're not in Auto mode.