# HVAC seems a bit quirky.



## jblackburn (Apr 14, 2012)

A/C always turns on when the system is shut off completely. It's very annoying, but that's how it's programmed.

Workaround: leave it set where you want, but leave blower speed on lowest. It'll remember that when the car is restarted (at least my auto climate control system does)


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## oldmillxxx (Jan 15, 2018)

Ugh! How annoying is that? Appreciative if it is hot and based on OAT it turns on for you, but to just turn on by default? Ugh, again!

Thanks.


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## obermd (Mar 3, 2012)

I suspect it's turning on because the car thinks it's going to be defrosting the windshield.


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## oldmillxxx (Jan 15, 2018)

Yes, the AC compressor comes on whenever you are in a Defrost mode (DEF/Mix/sometimes floor). This happens automatically to remove humidity from the cabin while blowing heated air across glass. It should not tell me that it is doing that (for this very reason...people asking questions). For safety purposes Recirc should never be used in a Def mode, and it is usually not allowed by the system with software that is written correctly. Almost a guarantee you will fog up with a cold windscreen while Recirc is on.

I guess I am chalking this up to poorly written code.


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## 17Hatch6MT (Dec 28, 2015)

I wish I had the option to tell the AC to stay off unless I turn it on. I like it off most of the time. I know when and when not to use the AC to defog. I understand it needs to run sometimes to keep the seals good. But otherwise, I'd like it to stay off unless & until I turn it on.

The more annoying problem I have with the HVAC is that when it's set to floor+windscreen, almost no air gets to the windscreen. I often have to put it on windscreen only to defog the window, even during normal drives with mild weather, with the car well warmed up, with good airflow or fan speed through the HVAC. Must be misadjusted from the factory. My fault for buying a first-run (Mexico-assembled Cruze) car, maybe.


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## oldmillxxx (Jan 15, 2018)

Two quick things. You should never have to use the AC (pressing the button) to control the defogging in the car. As stated above, this happens automatically when the Mode is placed in any Defrost position (Defrost/Mix). You can; however, use it as a preventative measure if it is warm, and you have high humidity in the car for some reason. This is all due to dewpoint and the temp of the glass. I'll let you research it.

I agree 100% on the lack of air moving across the windshield. This HVAC unit is poorly designed, but worse yet the control of it makes it worse. With the use of actuators to move the doors for mode, temp, and recirc instead of the old cable slides software controls it to whatever the manufacturer desires. Moving the mode door a small amount can change it dramatically. I also dislike the big jump in the blower detents from about the 2nd to 3rd positions. A lot of noise right away. That should not happen until you get up there higher. Blower noise is also part of the comfort rating and this car has noisy air flow.

I get it is not a luxury car, but these things matter. All of this can be made better with a software update. As someone that works in the biz, I do know that each model year there is (at least one) a new software release. IF a big enough problem is discovered, or the manufacturer deems it important enough, there can also be SW releases at any time. We are continuously updating the software in our controls. The only problem with this is getting it out to existing car owners. Typically, it is only done if there is a bulletin from the warranty group. As owners of these cars, we should be entitled to get anything new that is out there. It is one thing if they are adding a new feature for a new model year, but simply making an existing system function better (or in most cases the correct way) is another ball of wax. Cars' software are regularly shipped with bugs. As more an more electronics are crammed into our vehicles, this problem gets more and more amplified.


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## jblackburn (Apr 14, 2012)

Interestingly even in vent mode, AC off, if the windows start to fog up, even the manual climate control versions have a humidity sensor that will kick in the AC to defog the interior, then kick it back off. 

Noticed this going through the foggy/rainy mountains in a rental LT with just fresh air going. Very useful feature, but the Gen 2 AC gets COLD on a cold day. 

Sent from my SM-G950U using Tapatalk


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## oldmillxxx (Jan 15, 2018)

I thought of that, but wasn't sure if all Cruze models and trims have the humidity sensor, or not. For one product that my company has recently worked on, the Ford F150 has more than 30 variants. Every combination you can think of is a possible variant. That is why just having two, or three trim packages on cars doesn't tell the whole story all the time. Each trim package may have four to six options within themselves.

All of it gets very confusing for people trying to shop for exactly what they want.


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