I own a 2010 rx350 (non-navigation) and every time I turn on the car, the heating/AC takes ~40 seconds to be controllable. During this 40 seconds, no heating/AC buttons work. After the 40 seconds, the air will function as normal.

Part 2: The temperature and air mode settings will also reset depending on how long the vehicle was turned off. If the vehicle was off for 30 minutes to 1 hour, it will remember the temperature (after the 40 second stall), and it will start up in the last air mode used. If the vehicle is off for longer, it resets completely and you have to select your temperature and mode (... after the 40 second stall) to what you want.
Any ideas on what it could be?
We purchased the vehicle about 3 months ago. This issue started up a few weeks ago.

 

A knee-jerk response is ,,, bad/weak battery or terminals.

Have it tested.. if it passes then at least you can eliminate it.

Salim

 

Any updates to solution? I have the same problem and new battery/clean terminals. Noticed the issue a few weeks before changing battery.

 

Try resetting the system by disconnecting the battery for 15 - 30 minutes. You may have to then also reset your seats, radio stations etc.