# air con/heat controls



## ChevyGuy (Dec 13, 2014)

There are two types of A/C controls - the "manual" and the "automatic". Since you have a LTZ, I'd think it would be the automatic. When you move the control, you should see the temp and fan speed show up on the radio. (Assuming it's still the stock radio). Is that not happening? What happens if you change the fan speed?


----------



## Black Tammy (Jul 8, 2019)

Yes, the auto works great and has all summer. I can also go in and set controls manually using the mode button. That's where I tried to get my windows de-fogged many times this summer. Finally I realized the only way to keep my windows from fogging up is to use the auto setting, which now, in the summer, involves air conditioning. Now that's it's getting cold, I want to change my auto setting to involve heat, not air conditioning. The manual says that you should push auto button and then set the temperature. I don't know how to set the temperature, for the auto setting. That's my question. I'd like to stay with the auto setting, since the defrosting doesn't work worth a darn. I may have to take the car to the dealership. There may be something wrong with the temp control. It seems to me that if I just turn on the fan and nothing else, turning the temp control knob to red, should cause heat to come out of the vents. It does not.


----------



## Blasirl (Mar 31, 2015)

See section 8-3, about 1/2 way into the manual.



https://my.chevrolet.com/content/dam/gmownercenter/gmna/dynamic/manuals/2012/chevrolet/cruze/2012_chevrolet_cruze_owners.pdf


----------



## Black Tammy (Jul 8, 2019)

I really appreciate that but I have that manual and that's exactly where the source of my puzzlement lies; page 8-4 says 
"To place the system in automatic
mode do the following:
1. Press AUTO.
2. Set the temperature. Allow the
system time to stabilize. Then
adjust the temperature as needed for best comfort."
I don't know how to change the temperature other than with the red/blue temp knob, which does nothing when I move it. Maybe it's not functioning correctly or is there a way to set the temp numerically?


----------



## Blasirl (Mar 31, 2015)

And how long do you wait to decide that it's not working?

Put on high heat and drive for at least 5 minutes, or put on cold with the AC button on and drive for 5 minutes. What do you get?


----------



## Blasirl (Mar 31, 2015)

No air from vents!


----------



## Black Tammy (Jul 8, 2019)

Blasirl said:


> And how long do you wait to decide that it's not working?
> 
> Put on high heat and drive for at least 5 minutes, or put on cold with the AC button on and drive for 5 minutes. What do you get?


That's a good suggestion. Yesterday our weather was rainy, lots of humidity and I had a very, very hard time keeping my windshield defrosted. Had to pull over, it was so bad. I tried all kinds of combinations. I'll just have to keep experimenting but until the weather gets really cold, I probably won't know for sure. We're just now getting into 50-60 degree weather.


----------



## Brewster (Jan 24, 2019)

Hi there,

I have a 2012 Cruze LTZ and this is how my automatic climate works. 









20191006_171347000_iOS.MOV


MOV File



1drv.ms


----------



## Black Tammy (Jul 8, 2019)

So bummed, I can't get the video to load on my Mac. There must be something that it doesn't like! Brilliant that you tried to send me a movie and so disappointed that I can't see it!


----------



## Brewster (Jan 24, 2019)

Does this work for you? I uploaded it to youtube. I hit the auto button then I can change the temp with a dial. My car is in degrees as im in Canada.


----------



## Blasirl (Mar 31, 2015)

Black Tammy said:


> That's a good suggestion. Yesterday our weather was rainy, lots of humidity and I had a very, very hard time keeping my windshield defrosted. Had to pull over, it was so bad. I tried all kinds of combinations. I'll just have to keep experimenting but until the weather gets really cold, I probably won't know for sure. We're just now getting into 50-60 degree weather.


FIX: Excessive Moisture/Condensation/Frost on Windows 
Windshield defrost repair


----------



## Black Tammy (Jul 8, 2019)

Brewster said:


> Does this work for you? I uploaded it to youtube. I hit the auto button then I can change the temp with a dial. My car is in degrees as im in Canada.


Yes! That was genius to put it on youtube. Thank you! I found a way to change temps by hitting "mode", then using temp dial. But I was after changing "auto" settings and I think by using mode it doesn't affect the auto setting. I will try this method instead. I appreciate your help very much


----------



## oldmillxxx (Jan 15, 2018)

I work for an auto supplier, specifically HVAC controls. AUTO is just that, automatic temperature control. The only thing you should EVER have to change is the temperature setpoint to your comfort. The AUTO controls Mode, blower, and temp doors as conditions outside, and in the vehicle change.

As an example, say you are driving in the summer at the foot of a mountain. It is 90 degrees outside. You start the car and the blower runs high while blowing out the vents in the face of the dash towards you. As temps come down in the car, the blower ramps down with it, and the temp doors adjust from full cold, to somewhere in the middle based on your temperature setpoint in the car (let's say 72F). As you drive up the mountain the outside air temperature gets colder. Based on the algorithm GM uses, the temp doors will move more towards a heating condition, and the mode will move airflow towards flow and/or Defrost depending on glass temp, and outside air temp/humidity. This is all done automatically so that all you have to do it drive safely, and remain comfortable.

If you have an AUTO button on your HVAC, leave it on all the time. If everything is working as it should be, you will never have to turn it off. The only thing you might ever have to adjust is your preferred temp setpoint.

Hope this helps. Something that is rarely explained at a dealership. We have many warranty returns because many people do not understand how this feature works.


----------



## Black Tammy (Jul 8, 2019)

oldmillxxx said:


> I work for an auto supplier, specifically HVAC controls. AUTO is just that, automatic temperature control. The only thing you should EVER have to change is the temperature setpoint to your comfort. The AUTO controls Mode, blower, and temp doors as conditions outside, and in the vehicle change.
> 
> As an example, say you are driving in the summer at the foot of a mountain. It is 90 degrees outside. You start the car and the blower runs high while blowing out the vents in the face of the dash towards you. As temps come down in the car, the blower ramps down with it, and the temp doors adjust from full cold, to somewhere in the middle based on your temperature setpoint in the car (let's say 72F). As you drive up the mountain the outside air temperature gets colder. Based on the algorithm GM uses, the temp doors will move more towards a heating condition, and the mode will move airflow towards flow and/or Defrost depending on glass temp, and outside air temp/humidity. This is all done automatically so that all you have to do it drive safely, and remain comfortable.
> 
> ...


I am completely reassured now that I can get thru the winter with comfortable heat in my Cruze! Thanks for all the help (because the manual is sorely lacking!) I get it now. Still will have to hope defrost does a better job than it has so far tho'.


----------



## oldmillxxx (Jan 15, 2018)

In my honest opinion, the Cruze has the worst defroster I have seen in a vehicle. Anytime MODE is in any position that has Defrost in it, the air should automatically come on to rid the cabin of excess moisture. The Cruze does not appear to do that (could be for fuel economy by default). I always have to push the AC button to get it to work properly. I also have the Manual HVAC control (no AUTO button), so those with AUTO shouldn't have to worry about it. If it detects a need to defrost, it should default to that.


----------



## jrk27 (Feb 27, 2013)

I totally agree that the older Cruzes have the worst defroster, I own a 2011 LTZ. I personally never use AUTO because it seems to go from low to hi fan speed and doesn't use the middle fan speeds....but that's just me...


----------



## Black Tammy (Jul 8, 2019)

oldmillxxx said:


> In my honest opinion, the Cruze has the worst defroster I have seen in a vehicle. Anytime MODE is in any position that has Defrost in it, the air should automatically come on to rid the cabin of excess moisture. The Cruze does not appear to do that (could be for fuel economy by default). I always have to push the AC button to get it to work properly. I also have the Manual HVAC control (no AUTO button), so those with AUTO shouldn't have to worry about it. If it detects a need to defrost, it should default to that.


I always have to use AC to get the windows clear too! That's why I was concerned about winter coming, and how to handle this. I only bought this car this past summer. You've helped me a lot. Also, in saying that the defroster is terrible! Will have to figure something out.


----------



## ChevyGuy (Dec 13, 2014)

I'm pretty sure the A/C will come on if defrost is set. The light may not light, but that doesn't mean it's not on. 

One of the big issues is just getting the moisture that's in the car (such as slush tracked in) out of the car. You have to make sure you're pulling in fresh air so the air with moisture has to exit. Some people have discovered ice building up above the headliner. 

Also, the small economical engine doesn't produce much heat. Keep the fan speed down or it will never warm up.


----------



## oldmillxxx (Jan 15, 2018)

jrk, If that is how it is working, take it in. If it is only cycling from low to high to low, and nothing in the middle something is wrong. I will say, from an industry standpoint Chevy is known to have the worst algorithms for HVAC of the American Big 3.

Black Tammy, I'm glad you are more informed. It is a shame that more dealers do not explain this feature to consumers. It would help them a great deal.

ChevyGuy, while it does typically do what you are referring to (AC on while not lighting the indicator), the manual HVAC system does not seem to cycle it on long enough if it does at all. This is a safety concern if not calibrated properly in software, which it seems as though it isn't. Again, GM is not known for their algorithms. Your comment about the blower fan is moot. While it IS pulling heat away, it is only pulling heat from the heater core. The aluminum engines heat up quite fast compared to their steel cousins. The heating capacity of the system really doesn't care about the fan speed. When we calibrate a car, fan speed noise is more of a concern than the heat drain on the system.

I have the manual HVAC in my 2017 LT. I have learned that it is best run by hitting the AC button twice so that it runs in ECO Mode (greed indicator), and adjust the temperature to fit the conditions. This runs the AC while I am in Mix (floor/Def). I run Full Defrost if there is actually frost, snow, or ice in the colder months. I wish I had the AUTO button. I would never have to touch it, but that is not what I bought at the time. This deal was too good to pass up, so I went for the car that was used, but only had 1100 miles on it. Walked off the lot for $17K after all taxes.

Good luck to you all.


----------



## justin13703 (May 2, 2016)

I believe you’re overthinking it. As oldmill said, put it in auto and set the temperature. If you’re hot, turn the temp down a few degrees, if you’re cold, turn the temp up a few degrees, and let it do it’s job. Use the front/rear defrosters as needed.

As far as the ac coming on in defrost, it will run the ac in the defrost setting as long as it isn’t so cold that the ac is locked out to prevent compressor damage. At that point it is so cold outside (below freezing) that the humidity is low enough that the ac compressor isn’t needed anymore to reduce humidity inside the car. The fresh air coming in is dry enough. Freezing temperature air doesnt hold much moisture at all.


----------



## ChevyGuy (Dec 13, 2014)

justin13703 said:


> As far as the ac coming on in defrost, it will run the ac in the defrost setting as long as it isn’t so cold that the ac is locked out to prevent compressor damage.


And as long as the outside air temperature sensor isn't giving a crazy low reading (like -40) on the radio display.


----------



## ChevyGuy (Dec 13, 2014)

oldmillxxx said:


> Your comment about the blower fan is moot. While it IS pulling heat away, it is only pulling heat from the heater core. The aluminum engines heat up quite fast compared to their steel cousins. The heating capacity of the system really doesn't care about the fan speed.


I'm repeating what other Gen1 owners have experienced - put the heater on high and the engine won't even come up to normal operating temperature. The heater sucks all the heat out of the engine via the coolant. 

I have no idea how the Gen2 behaves. I haven't paid attention. But since OP has a Gen1, that's a moot point for now.


----------



## justin13703 (May 2, 2016)

The heater core is essentially another small engine radiator. Hot coolant goes in, the more air through the core, the cooler the coolant is going back to the engine. The heater running can have an effect on engine coolant temp in the cold. This is why it’s also said that if your engine is overheating, turn the heat on full blast because it will pull more heat out of the engine.

I know with the diesels (which is what I have) they don’t like to heat up very fast in the cold and you can actually watch the temp gauge drop if you turn the heat up.


----------



## chayonуx (Oct 6, 2021)

All that is possible is a defect. I don't think anyone could give you better advice than a specialist. The car is from 2012, and it needs refreshing to the air conditioning ventilation system. It would be best to pay a visit to specialists to see the situation of your air cone and in case of failure to fix it. I also had problems with the air conditioning from my car, but I thought everything was fine until I checked it. It doesn't blow as much air as it should, but I thought it was ok. The people from a company from my country told me it was a minor problem and solved it for me. Everything is effortless.





*___*


----------

