Air Conditioning Recycle/fresh air

[J Jennings]

Recently purchased my 2013 RX 350.  Was surprised the AC system does not automatically change from recycle to fresh air when the set temp is reached.   Now have to manually make the change when I realize air in the vehicle is getting stale.  Any body know why the vehicle was engineered this way?  I can not get a satisfactory answer from my dealer.  Any way to change the on-vehicle computer to make the system automatic?

[1990LS400]

Look at item #12 on the list of customizable settings in the document at the link I posted below.  It is possible that a prior owner had this setting customized so that the switch between modes is not automatic.   Lexus dealers and some repair shops are equipped to customized these settings.  If you want to try to do it yourself, the Carista smart phone app might be able to do it.  Carista requires a Bluetooth adapter that plugs into the diagnostic port under the dashboard. 

http://www.lexus.com/pdf/service/RX350_LPS.pdf

If you have a Lexus dealer do this for you, you might want to review all the other customizable features and have the dealer do everything you want at once.  Lexus dealers typically charge about one hour of labor to do this customization after the one free one that an original owner gets.