climate control behavior--normal?
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Lexus Test Driver
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From: PA
climate control behavior--normal?
I'll describe what I've observed, then explain later why I ask....the manual seems to offer very little. An oddity in the manual was that the AC may not turn on < 32F? I know that with a home central unit that could be disastrous, but would this imply there's no dehumidify when defrosting?
Anyway, the other day, it was 46F outside, and my car was set to top vents, fresh air not recirculate, not on AUTO. Temp was same on driver/pass, and 65. I was taken aback when I felt seemingly warm air coming through the vents.
The next morning, it was 39F, so I kept the same setting (65, vent, fresh). The air was coming in cold as expected, but as the car warmed up, warm air came in.
Today was 32F, and the warm air, with the above settings, was obvious.
I always avoid setting any car to AUTO. So I have always treated the temps, whatever the range may be, as just a glorified lever, from cold, to hot, as you would find in older cars. This does not seem to be the case, even when the LS is not set on AUTO.....
edit: cutting to the chase--what if I want outside air, when it is 45F (realistic), or even 32F? I guess the car must be on max cold? Doesn't max cold turn on the a/c, or maybe it does not? I also try not to activate the ac when not needed (these are habits I picked up from my dad).
Anyway, the other day, it was 46F outside, and my car was set to top vents, fresh air not recirculate, not on AUTO. Temp was same on driver/pass, and 65. I was taken aback when I felt seemingly warm air coming through the vents.
The next morning, it was 39F, so I kept the same setting (65, vent, fresh). The air was coming in cold as expected, but as the car warmed up, warm air came in.
Today was 32F, and the warm air, with the above settings, was obvious.
I always avoid setting any car to AUTO. So I have always treated the temps, whatever the range may be, as just a glorified lever, from cold, to hot, as you would find in older cars. This does not seem to be the case, even when the LS is not set on AUTO.....
edit: cutting to the chase--what if I want outside air, when it is 45F (realistic), or even 32F? I guess the car must be on max cold? Doesn't max cold turn on the a/c, or maybe it does not? I also try not to activate the ac when not needed (these are habits I picked up from my dad).
Last edited by Johnhav430; Nov 23, 2016 at 05:07 AM.
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Joined: Oct 2016
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From: Wisconsin
I would assume that any temp that you have it set for that is above what the outside air temp is will get mixed in with warm air from the system in order to arrive at the setpoint temp. So if you want to feel that really cool air you would probably have to set it to the lowest setting.
If you hit the climate button on your IP you will be able to see if your A/C is turned on or not...
If you hit the climate button on your IP you will be able to see if your A/C is turned on or not...
Thread Starter
Lexus Test Driver
Joined: Sep 2016
Posts: 8,588
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From: PA
This part I wonder about, because on newer cars, anytime recirc is turned on, the AC goes on, but it does not light up the AC led. Seems like older cars, you can turn off the AC, hit recirc, and continue to enjoy the residual of the dehumidified air. The reason it matters, is that it can be 55 outside, not hot, bordering on chilly, but a car would be hot. I wouldn't want to be set at 65, and have the car adding heat....our other 3 cars also have computer controlled climate controls, and if the setting is the min, be it 60 on one car, 65 on the other two, cold air from the outside will come in...even at 32F...
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Joined: Apr 2013
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From: KY
Automatic climate control sets a target temperature, like the thermostat in your house it will heat or cool at maximum capacity until it reaches the set point and will then maintain it. If you set it to 65, the car will try to get the interior temperature to 65, even with the fan off. It does not behave like a temperature lever and if you want the air cold you must set it to the max cold setting.
On a side note, care share why you have such disdain for the automatic mode? It's one of my favorite car features.
On a side note, care share why you have such disdain for the automatic mode? It's one of my favorite car features.
Thread Starter
Lexus Test Driver
Joined: Sep 2016
Posts: 8,588
Likes: 392
From: PA
Automatic climate control sets a target temperature, like the thermostat in your house it will heat or cool at maximum capacity until it reaches the set point and will then maintain it. If you set it to 65, the car will try to get the interior temperature to 65, even with the fan off. It does not behave like a temperature lever and if you want the air cold you must set it to the max cold setting.
On a side note, care share why you have such disdain for the automatic mode? It's one of my favorite car features.
On a side note, care share why you have such disdain for the automatic mode? It's one of my favorite car features.
More observations. Yesterday, the outside temp was 50F. With identical settings, cold air came in through the vents, as I would have expected. Actually, a little chilly for my tastes. So as an experiement, I put all the windows down, and now the cabin was chilly. THE HEAT NEVER CAME ON.
So my hunch is that somehow the outside temp influences what goes on, but wtf do I know, I am only observing. A Lexus engineer could certainly reveal what they designed this system to do. The manual is useless, as they often are.
Probably old-fashioned, why would I want a car deciding what fan speed is appropriate. And in the event the a/c is cycling, I don't like that parasitic draw without my consent lol
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