Globeman

Now that we’re starting to see colder weather and the need for heat I’ve noticed that the AC light always comes on when I press AUTO. Even if the temp is set for 70°F and it’s cold in the car, the AC light comes on. If I hit the AC button, both lights go off.

It doesn’t seem like there’s any way to have AUTO temp control for heat without having the AC on. Is something wrong – it shouldn’t be like this?

meyerweb

Yeah, I notice that a lot, too. I'm not sure if it does it ALL the time, but certainly a lot of the time. Other cars I've had with auto climate control do the same thing.

6spdC6

Thats the way mine works. Also I have found now that it turned cold that to get the heat I want I have to set it at close to 80 degrees. FWIW It seems to me that the temperature setting has no sense to what the real inside temperature is, hence the AC running!

O well mostly a moot point now in a few days it goes away for its winter sleep, we hit 25 degrees last night and its only 32 now.

thrilled

I think whoever invented the auto thing wasn't using common sense.But I've seen that quite a bit through my life.When engineers come up with something they should have A more normal person,average IQ to check it out.
Anyway I don't use auto.

BenCasey

AC dehumidifies the air. If its cold and wet, that's exactly what you need; nice dry air. You should be able to turn off the AC and retain AUTO.

I can't verify, my car isn't in for 2 more weeks...

defaria

Exactly! The C in AC != Cool. It's "conditioning" and dehumidifying is one those functions.

Globeman

Cool, crisp, dry Fall air. The AC stays on as long as it's in AUTO. I've tried driving like that thinking that it would eventually go off. It doesn't.

On my other cars, the AC comes on with the defroster to dry the air - makes sense. But why can't you have AUTO heat without running the AC in a C7? Besides chilling the air when you want heat, it's a hit on performance & fuel economy.

It's either a really dumb design or a widespread malfunction.

meyerweb

Actually, you can. You never really have totally manual control in this car except when the temp is set to Lo or Hi. If you're on auto, and press the AC button to turn that off, the car still tries to maintain the temp you've set on the ****.

Globeman

Interesting. I'll have to try that out. I thought that not having the AUTO light meant that you were manually controlling the temp like cars of old. Unfortunately, most of my trips are local so it may take a while to confirm this. Thanks for the info.

But it's still a really dumb design. Not much point having an AUTO button if it's always in AUTO anyway.

C751ZF1

I have the same auto climate control crap om my MB. and Porsche, hate it...

Steve_R

Why? What's the difference? Unless the AC light was on you wouldn't know whether it was on or not.

TEXASRANGER

Correct. prevents and keeps fog off the inside of Windows.

thrilled

[QUOTE=TEXASRANGER;1590719771]If you don't want the Windows foged up you put the defroster on.

trivette

My wife's previous SRX had the same kind of setup. A "snowflake" (A/C) would light up when in the auto mode whether it was 80 above or 10 below. Never did figure out the logic of that. Her new one has the CUE system and that has changed. The system on my '14 operates like all of you have described, although I still recall older cars I've owned where auto simply meant auto and you got heat or A/C without trying to beat or challenge the system.

Indy-hp

All I know is that the Auto function works in my car year-round. The ac light may only mean that ac is available to the auto climate control, not that it is actively running.

Also, in my C5 and C6, the ac would blow from the top vents when the sun was shining in the windshield to offset the effect of the sun, and blow warm air on my feet to maintain the cabin temp I set. I believe the C7 does the same thing. Pretty smart system really. Just set the temp and forget.

kevincol

It is to keep humidity out of the air so that your windows don't steam up from the temperature difference from the outside and inside of the car. I did this on all my C5's also when in auto.

wbrands

It works the same on both my cars with auto climate control. In addition to humidity control, it might also have something to do with individual passenger/driver control. You can't set one side lower than the other if all you have running is heat. I don't think the compressor clutch engages unless A/C is required to satisfy the settings.

HolyRoller

Exactly. A complicated system does not have to operate in accordance with simple-minded preconceptions. If you're hot, reduce the temperature and turn on the seat vent. If you're cold, increase the temperature and turn on the seat heat. If you're riding in cold weather with the roof down, crank the dial to Hawaii (it says "HI" instead of a number, which stands for Hawaii of course). Give it a few minutes to work, and if you're still hot/cold, repeat as necessary. On semi-cold days, I tend to start at about 74 and gradually turn it down to 70 as the trip goes on.

Those who say just turn on the defog if the windshield fogs up, have you noticed that after a few minutes condensation spots form and they only go away if you turn the defog back off? Wouldn't you rather have a smart system keeping the fog away to start with?

alienranch

Correct

BigJoe

I noticed the past few days where the temps in the DFW area were in the 50-60s that when starting the car the AC is on and you get a blast of cold air even with the temp set at 75 or so and the inside is at 60. It was so bad yesterday that my wife turned all the vents away from her (which made them blow on me, of course...) It is worse when the car is parked in the sun, I guess the computer thinks "Sun -- must be hot."
Just an observation, no solution...