Climate Control System Atc

[6month]

04 RX 330 I have trouble regulating the temperature to a comfortable level. This is my first Lexus/Toyota product. Since it has been cool lately 75 seems to warm the car up any lower and the air is too cool, but soon it gets too hot and then starts blowing cool air from the upper vents. AC is switched off. In the summer the temp once it levels out is either too warm or too cool. Maybe I am too senstive? I have owned numerous domestic branded vehicles with ATC and they seem to function well at 70 degrees. My last SUV before the RX was a Infinity QX4 and I could set the temp at 70 degrees and it fuctioned perfectly year round at that temp. I have been used to set it and forget it and let the ATC do its job. This RX330 I seem to always be fiddling with the temperature to balance the cabin temperature.

Is there an adjustment ? Or am I just not getting it right. I have not read the novel in the glovebox to see if there are any tricks or tips. I am still under warranty should I take it in.

Signed, Hot or Cold in Texas B)

[wwest]

04 RX 330 I have trouble regulating the temperature to a comfortable level. This is my first Lexus/Toyota product. Since it has been cool lately 75 seems to warm the car up any lower and the air is too cool, but soon it gets too hot and then starts blowing cool air from the upper vents. AC is switched off. In the summer the temp once it levels out is either too warm or too cool. Maybe I am too senstive? I have owned numerous domestic branded vehicles with ATC and they seem to function well at 70 degrees. My last SUV before the RX was a Infinity QX4 and I could set the temp at 70 degrees and it fuctioned perfectly year round at that temp. I have been used to set it and forget it and let the ATC do its job. This RX330 I seem to always be fiddling with the temperature to balance the cabin temperature.

Is there an adjustment ? Or am I just not getting it right. I have not read the novel in the glovebox to see if there are any tricks or tips. I am still under warranty should I take it in.

Signed, Hot or Cold in Texas B)

Since my first purchase of a Lexus, a new 1992 LS400, I have learned quite a lot about the shortcomings of the Toyota and Lexus automatic climate control system.

The best procedure is to NEVER allow the A/C compressor to operate if the climate is cool enough that it is not needed for cooling. As of 2001 Lexus had two c-best options that allowed you to, 1, disable the A/C indefinitely, and 2, unlink the A/C from operating automatically in defrost/demist/defog mode.

In the meantime you should make it standard practice to prevent the system from automatically switching from footwell, heating mode, to dash, cooling mode. It will do this automatically even in cool weather as soon as the cabin temperature rises nearly to your setpoint. raise the setpoint it switches back to footwell, but as the cabin temperature again rises to your setpoint you will again get very discomforting cool and dry airflow to your face and upper body via the dash outlets.

NipponDenso, Denso US, has a US patent that decribes a unique (flawed) technique of their climate control design. Basically "upper" airflow from the system can be as much as 20F cooler than lower system airflow. So yes, when the climate is such that your landscape "surround" is on the coolish side the Denso cliamte control can be very discomforting if left to itself to manage automatic functions.

Shame, really.

Oh, newer Toyota and Lexus vehicles have a third c-best option that prevents the system from switching from footwell mode automatically.

Google for "wwest denso demist" for a LOT more information.