Climate Control: can anyone tell me what "auto" is supposed to do?

[SIO2GA]

I bought my Jeep back in late March and didn't use the heat much before it was AC time. I did notice when I had the heat on that if I set the temperature to 74 and hit "Auto" that it started blowing wide open and blowing at the windshield and at the floor. It didn't blow from the mid-lever ports near the screen and near the steering wheel and the opposite side. That just didn't seem right and I've only tried "Auto" once or twice. I thought the only time the fans blew towards the windshield was to defrost? Can anyone tell me where the fans or supposed to blow? I suspect that something was wrong from day one. Now in late winter I'm having issues with the driver side blowing very cold outside air and the passenger side blowing max hot air when the temp is set to 74 for both sides (synced). This is a new problem for me and it was no fun when I was travelling in Eastern New Mexico two weeks ago on I-40 and the low temperature was 10 degrees. I have it scheduled to go in for service in three weeks and I'm just curious where the fans blow when set to Auto for other people? Another problem is that when the vehicle is cold and started, even when I have the temp set to 74 it will get extremely hot, especially when the car first reaches a normal operating temperature. Usually if I just leave it alone it will moderate and start blowing mildly warm air. If this thread isn't in the best place perhaps a mod will move it where it should go. Thanks all!

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[OHJeeper]

That's not the experience I've had with mine. Your first paragraph, when set on heat, I have also noticed that it favors the floor/windshield vents but the other things sound like a problem to me.

If you have JSCAN or another scan tool you can check the temp sensors within the cabin and see if something is out of whack - or just take it to the dealer if you're still under warranty.

I have mine set to 72 pretty much all the time and mine is steady eddy, no crazy temp swings like what you described.

 

[sharpsicle]

It will change the vents used and the intensity based on different situations. I don't think there's a one-answer-fits-all to Auto mode, it just does its thing and will change what that means to combat changes. Your issue sounds almost like there's a bad sensor.

FWIW, my Auto has never made me question things. Sometimes it's using the windshield vents, sometimes the dash, other times the floor. Sometimes heat and sometimes cool. I just trust it, and it hasn't let me down.

 

[Gvsukids]

I did notice when I had the heat on that if I set the temperature to 74 and hit "Auto" that it started blowing wide open and blowing at the windshield and at the floor.

My Jeep does that when I use the remote start and the temperature outside is cold.

 

[ChrisNLA]

I have found mine to be a bit unpredictable in certain circumstances. Usually if the weather is close to my comfort zone (like its 77 outside and I want 70 in the truck) it doesn't seem to know how to get to my comfort place and I just override it. If the weather is at one extreme or another it seems to do fine, other than occasionally it just wants to blow at the windshield and I'm like 'Bruh, I'm cold, I want the air blown at ME' and I override it.

So - probably half the time I'm using manual controls, which is totally fine because in nearly 20 years of driving this is the only vehicle I ever had with auto climate control. Not a huge deal.

 

[BearFootSam]

I bought my Jeep back in late March and didn't use the heat much before it was AC time. I did notice when I had the heat on that if I set the temperature to 74 and hit "Auto" that it started blowing wide open and blowing at the windshield and at the floor. It didn't blow from the mid-lever ports near the screen and near the steering wheel and the opposite side. That just didn't seem right and I've only tried "Auto" once or twice. I thought the only time the fans blew towards the windshield was to defrost? Can anyone tell me where the fans or supposed to blow? I suspect that something was wrong from day one. Now in late winter I'm having issues with the driver side blowing very cold outside air and the passenger side blowing max hot air when the temp is set to 74 for both sides (synced). This is a new problem for me and it was no fun when I was travelling in Eastern New Mexico two weeks ago on I-40 and the low temperature was 10 degrees. I have it scheduled to go in for service in three weeks and I'm just curious where the fans blow when set to Auto for other people? Another problem is that when the vehicle is cold and started, even when I have the temp set to 74 it will get extremely hot, especially when the car first reaches a normal operating temperature. Usually if I just leave it alone it will moderate and start blowing mildly warm air. If this thread isn't in the best place perhaps a mod will move it where it should go. Thanks all!

I think what is happening is that the climate control system is looking at your temp setting in the context of the interior and exterior temperatures and selecting a defrost algorithm. An experiment to try would be to set the thermostat to 69 and see if it behaves in the same manner. I do know that the AC will engage during Auto even though the AC light remains dark. The AC of course is used to reduce cabin humidity in conjunction with the heat to defrost / defog the glass.

Like @sharpsicle mentioned, mine too will behave in the same manner if I remote start it, presumably as a warm up/defrost function just as the wheel and seat heaters kick on to get it all toasty for me.

Sometimes these systems can be too clever. The Owner's Manual has a pretty in-depth description of the system's operation that should help.
As the cabin comes up to temperature the fans should slow down and the vent outputs may change.

 

[Redfour5]

I bought my Jeep back in late March and didn't use the heat much before it was AC time. I did notice when I had the heat on that if I set the temperature to 74 and hit "Auto" that it started blowing wide open and blowing at the windshield and at the floor. It didn't blow from the mid-lever ports near the screen and near the steering wheel and the opposite side. That just didn't seem right and I've only tried "Auto" once or twice. I thought the only time the fans blew towards the windshield was to defrost? Can anyone tell me where the fans or supposed to blow? I suspect that something was wrong from day one. Now in late winter I'm having issues with the driver side blowing very cold outside air and the passenger side blowing max hot air when the temp is set to 74 for both sides (synced). This is a new problem for me and it was no fun when I was travelling in Eastern New Mexico two weeks ago on I-40 and the low temperature was 10 degrees. I have it scheduled to go in for service in three weeks and I'm just curious where the fans blow when set to Auto for other people? Another problem is that when the vehicle is cold and started, even when I have the temp set to 74 it will get extremely hot, especially when the car first reaches a normal operating temperature. Usually if I just leave it alone it will moderate and start blowing mildly warm air. If this thread isn't in the best place perhaps a mod will move it where it should go. Thanks all!

Auto means it functions like your thermostat at home. It is designed to function as a negative feedback mechanism which is actually a positive thing... When the temperature gets to the temp you have specified it will go into maintenance mode. So, if you turn it on auto and its 10 degrees out, it goes full blast to get the temp to where you specified as soon as possible at which point it will "calm" down... And that feature works for both you and your passenger separately....well to a certain degree.... Get it.

 

[Viper501]

What @Redfour5 said.

My wife doesn’t seem to ’get’ that algorithm either. She and my son will both turn it to 80 to try to warm it up quickly without understanding if you set it for 72 it will get there as quickly as it can then calm down. 80 won’t get it there any faster.

I use the auto function almost exclusively except when I need to force the A/C compressor on when the interior humidity needs to be dried out (i.e. the windows are fogging up).

When in auto the truck decides which vents to use and how. I really do not notice it making mistakes in those decisions.

The only ’glitch’ I do notice is that it will every now and then open up on the passenger footwell and blast outside temp air. Having read other threads this appears to be a ‘normal’ part of the algorithm to defrost the coil. It will do it for about 30 seconds then shut off and go back to normal.

 

[SIO2GA]

Thanks everyone! I will try it out on auto and let it run a while and see what happens. First I need to get it fixed because it's still blowing cold air on the drivers side and hot air on the passenger side.
I do wish that "Auto" mode would blow from the dash with warm air at least for a little while when you first start the system. I'll give it a try once the dealer has fixed whatever is wrong with the climate system. At least now I know that when I first tried it when new that it was doing what it was supposed to be doing.

 

[Great Offender]

t's still blowing cold air on the drivers side and hot air on the passenger side

I'm living that dream now. I have hot on the drivers defroster and cold on the passenger. Sent me home and I'm waiting on warranty parts.

 

[LouisvEarlleJT]

For the cold on one side and hot on other issue, make sure your "sync" button in the climate control screen is checked. If it got unchecked at some point you could be cranking up the driver side, or vise versa, and creating this phenomenon.

 

[Great Offender]

For the cold on one side and hot on other issue, make sure your "sync" button in the climate control screen is checked.

This was definitely mechanical as they had to order parts but I appreciate the heads up. I don't think I've ever looked. In any case it only happens to "me" with defrost.

Like the OP I had had mixed results with auto. Sometimes I guess it reaches cabin temp and then almost feels like it's blowing cool? Maybe it has reached its optimal temp? Heat in S. TX is a rare occasion for me so I don't miss it and I'm usually by my self when driving.

 

[Wheelin98TJ]

I thought auto was just for temp and fan speed.

It changes where the air blows from too? I've never really noticed.

 

[Great Offender]

It changes where the air blows from too?

Surprise!

 

[Badunit]

Auto controls the temperature of the air that is blowing, the fan speed, and which vents it blows from. It will use defrost + footwell when it thinks the windshield might fog. It will switch to vents and blow cold air on you when it reaches/exceeds the set cabin temperature and thinks it needs to cool you down. My Ram has the added "feature" of temperature drift where, after it has warmed the cab to the proper temperature, I have to increase the temp setting by 2 additional degrees every 15-30 minutes to get it to quit it blowing cold air on me.

Manual mode lets you set the fan speed and which vent it blows from. The temperature of the air that is blowing is still "automatic". It is not actually "manual" like the old style AC controls were.

I much prefer the old style controls of a temperature slider/knob, fan speed control, and vent selector. It always blew the correct temperature air at the correct airspeed from the correct vent(s), it reacted instantaneously, or nearly so, to any changes in those selections, and it never switched to blowing cold air on me in the wintertime.

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