Threxx

On my 99 GS400 there are two "auto" settings. The first one seems to deal with temperature and is on the left hand side of the climate control settings. If I turn that one on, my A/C light turns on. The air doesn't actually seem cold, but the light still turns on. However I can turn it off manually if I want to. BUT if I want to turn the other "auto" switch, which is turned on by switching between 'fresh air', 'recirculate' and then 'auto', it insists on keeping the A/C light on. If I try to manually turn the A/C off it turns the second 'auto' light off. I'm assuming the A/C light just means that the A/C compressor is on, not that it's necessarily cooling, because even if it's 20 degrees outside and the car is blowing hot air all over the place, the light stays on.

I think I've seen it a couple of times with both switches set to "auto" and the A/C light is actually off, but it's so rare that I'm not even sure of it.

Is this normal?

FilBoiLsGs

The upper portion "auto" switch is for the air sources: from inside the cabin, from outside the cabin , and when in auto mode, when the sensor detect high polutants from the outside source, it will automatically shut off the outside mode and recirculate the air inside the cabin. After a while you can observe that the recirculation mode will shut off again and get air from the outside. When you start the car, you can manually press your selection. I press mine in auto mode all the time. The lower left "auto" is for the whole cabin automatic climate control system. When you are in dual mode, each passenger in the front can adjust his own preferred temperature settings. Thus, the driver can select 75 degrees while the passenger can select maybe say, 80 degrees. The "A/C" green light is on even when the system is blowing hot air in winter *heating system* . The system is very intuitive that it delivers the right selected temperature whether it would mix hot air and cold air to come up with the right temperature selected. It was also explained to me that this would help minimize the fogging of the windows compared to the conventional system where when its hot its hot and when its cold its cold only. I also observed in my LS430 that the system works in conjunction with the glass heating system throughout the cabin. For example , rear passenger at the right side's temperature is 78 degrees. When the angle of the sun is in direct to that particular area, the temperature therefore would increase, let's say to 82 degrees. The system will blow some more cold air into that air register to bring back the temperature to around 78 degrees again. The same operation can happen to other parts of the cabin depending where the sun is facing. High Tech HUH?????

To add to the confusion...the seat heating system will not work when the outside temperature is not low.
It should be around 45 or 55 degrees (check the nos.) for the heater to heat up otherwise, eventhough the seat heater in on, it is not hot unless the outside temp is very low.

I also observed in both GS and LS that in winter eventhough the A/C system is OFF and when I drive in the freeway with my sunroof open, there's warm air blowing inside the cabin as if you dont need to turn on the heater at all when roof is open. Just my personal observation....

FilBoiLsGs

Threxx,

This is the exact wordings I've got from the literature hidden in my glove compartment.

"Nobody should have to breathe polluted air, so you Lexus features an advanced air filtration system.

Smog sensors sample incoming air> I f the levels of certain pollutants rise too high, the system closes

off the air intakes and recirculates the cleaner air already on board. Air is charcoal-filtered on the way in,

helping to eliminate many forms of pollen, along with sand and dust particles. Odors and other pollutants

are continously filtered out of the interior environment by the sophisticated air filtration system, and carbon

dioxide build up is minimized with a fresh air that mixes the inside air with oxygen-rich outside air."



Why don't you just turn both switches to auto and you just select your temperature and let the system do its job? Even when you turn both "auto" switches off ,the green light in the air intake is still on.

FilBoiLsGs

This topic might end up someone......opening another topic entittled??????


Why Do Luxury Car Drivers Roll Down Windows, Shut Off A/C's and Save Gas?

LOL....LOL...LOL

P.S. I only open sunroof, A/C ON!!!

Iceman

Especially since you don't save any gas by turning off the A/C and rolling down the windows. Studies have proven that the increased drag from running with open windows almost exactly matches the decrease in mileage caused by running the A/C compressor...

chrisgs

it happened to my 2000 GS300 too. whenever i turn on the auto mode, the A/C light automatically turn on even the outside temperature is below 0. i don't know why, any one?

Threxx

Well first of all I'm not asking this because of the gas, I'm just asking what's the purpose behind it?

If anything I just don't like knowing that I'm losing 5-10 horsepower to the A/C

And furthermore, I honestly don't like A/C unless it's just horribly hot and humid (like I mean 85+ degrees and 70% humidity). I prefer to feel the natural breeze blowing in my face. Not artificially cooled and filtered air from the vents. I get enough of that sitting at home and in the office.

doug_999

I'll assume that everyone here lives in warmer climates and thus have never had your windows fog up while driving.

First off,
When you have the auto recirc turned on (the one that will switch to recirc when it detects pollutants), you have to have the AC on (the car does this for you automatically and you can't override it). Turn off the Auto Recirc and you can turn off your ac and still leave it on auto temp settings.

The reason for this is that when you put the car into recirc mode and it is cold outside, your windows fog unless you have the air conditioner on to remove the moisture from the air. There obviously is a liability issue here for Lexus and thus they force the air on.

Japanese and German cars tend to be the only cars that allow the driver to actually turn on recirculation - Most American cars do it with the Max Air-conditioning setting (note Max=Recirculate).

That said, it is funny to see people here in Chicago driving around with their windows all fogged up - because they unknowingly have the recirc turned on and the AC off. Note this is normally only possible in lower end cars and most higher end cars tend to automatically turn the air conditioner on if you go into recirc mode - even manually. I did notice that my GS will allow me to go into Recirc mode manually and still turn the air off. My BMW wouldn't allow this - it always turned on the AC if I went into recirc mode - however it didn't require the AC to be on if I was in auto mode.

So the short answer is, if you want auto recirculation on, your air has to stay on - if you don't want the air on all the time, turn off the auto recirculation mode.

Doug