wgregt

Anyone seen this? Driving with the AC on and that recirc button on and it turns off on its own randomly and fresh air comes into the cabin. No real repeatable time or instance. Pisses me off.

Clutchless

Check the owners manual. If you have Navigation, it is in the navigation owners manual.

salimshah

I know it is not functioning as "you" desire, but keep in mind even in re-circ fresh is is still pulled in.
If you want more control, turn off the Auto mode of air conditioning. Automation does lot more than maintaining the temperature. Personally I think Lexus went overboard with airflow in cabin, but trust me that in middle east the affluent vehicle owners park their European vehicles and use Lexus in the summers .... just because of the automated AC cooling.

Salim

wgregt

I don't have the nav model. Just have the button on the dash.

wgregt

Maybe I'm not being clear. I'm asking: Anyone know WHY the recirc button, on it's own, would randomly go from lighted/on/in use to unlighted/off/not in use?
Mine randomly shuts itself off, thus allowing in air from outside the cabin, when I have the AC on, and the recirc system closed. Just driving, and all of a sudden I have fresh/hot air from outside. Reach down, press/relight/turn on the button yet again. It's not repeatable: not under acceleration each time, not under braking, not in the day/night only, etc. Just random.

Anyone else here ever had this happen?

salimshah

No, you are pretty clear in what you are asking.
I shared my best way to diagnose. Automation has built layers and we have to narrow down if there is a problem or it is a "feature".

Salim

hankrearden

An important question is: does the recirc function go off and stay off for the duration of your trip, or does it eventually come on again?

The latter is normal - in auto mode it alternates between on and off for reasons known only to Lexus's engineers.

The former is not normal. If it changes to fresh air and never returns to recirc, then something is wrong. I don't know what that might be.

wgregt

Well...more data needed for that. It certainly goes off on its own and...I turn it back on. If it's supposed to come back on, I can't wait that long. The air gets stale and warm-ish and I have to click the damn thing again to turn it back on. Had no idea that this is...by design? Come the F on. So now I need to wait it out and see?
How in the world would the auto on/off be a feature? What's to be gained?

hankrearden

As I wrote I don't know what might be wrong. "Auto" mode should just be a set and forget kind of thing, and it works well in the moderate climate in which I live. Recirc might come on and off; I don't even know nor do I care. The cabin remains comfortable. Clearly that's not the case for you.

Best wishes.

salimshah

There are differences in models and some differences are listed in the owners manual [but then you need to have all the manuals in front to figure out the differences].

A while back heat & cool were two separately controlled systems. These days the thermostat sets the temp and "Auto" seamlessly switched between heating and cooling. Auto also compares the inside temp, thermostat setting difference to the inside temp, amount of sun entering the cabin, humidity inside cabin, engine coolant temp and then controls blower motor speed [fan speed] and direction of air flow [mode]+ recirc door flapper. All this is built in to the programming. You will notice that in Auto in winter time the blower does not push air till the coolant in warmed up.

In summary 'Auto' is more intrusive than being a simple switch.

Pleas note, we [at least I] have not tried to suggest a fix to the the 'conditioning of air' as you desire. I am responding only to 'recirc' button and its unexpected behavior.
Discussion on conditioning will get into cabin filter, proper condensate draining, wet carpets etc.

Salim
[I hope I am shining light on the issue and not making it more complex]

mcomer

Excerpt from Lexus TIS, Toyota Information System:

Automatic Recirculation Control

Automatically changes the air inlet mode to fresh air or recirculate mode according to the level of harmful elements in the outside air, cabin temperature, and outside temperature.

• The air conditioning amplifier detects harmful elements (CO, HC and NOx) based on smog ventilation sensor signals and automatically switches air inlet mode to recirculate air mode to prevent such harmful elements from entering the cabin.
• The air conditioning amplifier detects room temperature based on a room temperature sensor signal and automatically switches air inlet mode to recirculate air mode to prevent the room temperature from becoming too high.
• The air conditioning amplifier detects outside temperature based on an ambient temperature sensor signal and automatically switches air inlet mode to fresh air mode to prevent the windshield from fogging up.
• Neural Network Control
  
  (1) Previously, in automatic air conditioning systems without neural network control, the air conditioning amplifier determined the required outlet air temperature and blower air volume in accordance with the calculation formula that has been obtained based on information received from the sensors. However, because the senses of a person are rather complex, a given temperature is sensed differently, depending on the environment in which the person is situated. For example, a given amount of solar radiation can feel comfortably warm in a cold climate, or extremely uncomfortable in a hot climate. Therefore, as a technique for performing a higher level of control, a neural network has been adopted in the automatic air conditioning system. With this technique, the data that has been collected under varying environmental conditions is stored in the air conditioning amplifier. The air conditioning amplifier can then perform control in a way that provides enhanced air conditioning comfort.
  
  (2) The neural network control consists of neurons in the input layer, intermediate layer and output layer. The input layer neurons process the input data of the ambient temperature, the amount of sunlight, and the room temperature based on the outputs of the switches and sensors, and output them to the intermediate layer neurons. Based on this data, the intermediate layer neurons adjust the strength of the links among the neurons. The sum of these is then calculated by the output layer neurons in the form of the required outlet temperature, solar correction, target airflow volume and outlet mode control volume. Accordingly, the air conditioning amplifier controls the servo motors and blower motor in accordance with the control volumes that have been calculated by the neural network control.
  

salimshah

Please share the objective for manually setting the Recirc and may be we speculate on how to get to what you desire 'conditioning part'.

There may be some other reason why we have the the condition you have in your vehicle.

Salim

wgregt

Me? I'm just trying to get the recirc button to go on and stay on. In my world, I'D be the one to determine if the interior is how I like it, and then be able to leave the system on. Seems the engineers have other ideas from the info you guys posted here. Guess the end user/buyer doesn't get to have it their way.

hankrearden

If you turn off Auto mode, and then press Recirc (or set it whichever way you want it set), does it stay that way?

I can't help but think something is wrong. In light of mcomer's detailed explanation Auto mode does a lot more than I thought it did.

salimshah

Do give a try with Auto off. Personally I drive with Auto OFF and set the mode to blow from the top vents in the summer and feet level in the winter. These servos are over worked in Auto mode.

On Recirc side, if I engage it, it helps heat and cool faster but the air gets stale for my taste. My wife engages recirc when her all allergies are high. So mostly it remains off.

The only thing we did not discuss is the defrost. That would prefer AC on, and air directed to the windshield (mode). They are on timer and I think they turn off in 10 mins.

I do feel in control.

Salim
PS: One of the most talk about issues in Lexus is the mode servo wearing out. ~100k miles.