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FCA Cross-platform HVAC Issues

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#1
Has anyone else experience/noticed a problem with their HVAC? On my last car (2019 Scat Charger) it was so pronounced I had to get a lawyer. Now I have a 2019 Durango and Hellcat Charger and the weather is changing I am noticing the same issues, just not as pronounced. I have began to think its an issue with the sensors and programming, or a combination thereof. All my non-FCA cars were fine. If I set the temp to 68, the air blows out at 68, whether it's AC or heat. You tell it what temp to blow, and in the case of heat it adjust the flaps till it measure the mix of air at the temp you set, simplistically speaking of course. But with all my FCA products: 5 Jeeps, 5 Chargers, 1 Avenger, 1 Durango; it seems like the HVAC has a mind of it's own in almost all of my cars. Soon as the weather changed last year I noticed my heat when set to 67-69 degrees would just randomly start blowing hot. I took it to the dealership multiple times and at first they said "Could not duplicate" which was ridiculous because it was doing it every time I drove the car. So I bought an infrared thermometer and started recording videos. Usually it would blow around 135 degrees but numerous times the air was coming out at 180 degrees plus. Contrasting with the heat, sometimes it would blow cold. No, the "Auto temp" was and is not ever used in my car. Now that the weather is changing I have noticed in both of my cars its doing the same thing. At this point I chalk it up to an engineering flaw. I know some people, or my grandma, don't mind the heat blowing and when riding with others I am usually uncomfortably hot. So even when its 10 degrees outsitde, I like my cabin temp to be around 67-69 degrees. I have tried everything to remedy the situation. FCA deflected for so long on my Scat Pack that I was literally days away from selling all 3 of my current Fleet and changing over to Ford and Chevy. Luckily the dealership brokered a deal and made everything work out. But all the surveys, JD Power questionaires, emails: every time I wanted to have this issue addressed I got the same standard responses which were lackluster at best. It was like they heard what I was saying but did not really listen. Now I have 145k worth of Dodge products in my driveway I am just mostly disappointed. The fluctuations are not enough to make me go thru the buyback process again, but it just makes me upset I spent so much of my hard earned money and time of my life (60 months in a combat zone...thats 5 YEARS!) and I get a manufacturer that can't admit there is an issue unless its between STAR techs and dealership techs that is not supposed to be made public. I am hesitant to post those on here for now, I just want some kind of answer. I have work to do for now, so I will post this for now and update as I go with more info, answers to questions etc. Thanks for everyone's insight. Dodge, I await your rebuttal.

@DodgeCares
 

Diboblo

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#2
I know this is an older thread, but I had similar issues in my 15 HC Charger.

I replaced the humidity sensor, up by the rear view mirror and haven't had a problem since.

Others have reported this, on LXForums and this also solved their problem.

It isn't cheap, at about $80, but it fixed our issues and they haven't come back.

My car had a code set, but not a light. It also did not show up, with the on board diagnostics. I used AlfaOBD to scan my BCM and found it lurking.

Replaced the sensor and cleared the code. No more issues, since early summer, 19.

Bob
Riverside, California
 

BULL

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Hickster

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#4
That is what it is supposed to do. A 3 way system that has a by pass valve will use the valve to blow the temp no matter heat or cool. In stead of all the way on or off it by passes with a valve that keeps up with the ambient tempt set on. Cheap settings will be off or on this one is a mixing valve. It will keep the temp of the required ambient temp. It will keep blowing to keep heat or cool. Nice system,, not like at home. Either on or off.
 

Hickster

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#5
Bob, from Riverside Cal, you are on the mark, but to go a step further, add a dew point sensor. A step above the humidity but to measure the exact moisture in the air. There is a misconception of umidity and dew points. I have measurements in each room in the house that reads both. Been in the systems for a couple of years. That is why the chiller killer does not do all it is made to do. One system blows on and off where one as a mixing valve that will control the temp, humidity, and dew point not just to dump cold air in the system. That can actually make the system worse. Walk into a store and the windows are fogged up with moisture?? Dumping too much cold air but not lowering the dew point. It is raising the dew point adding more moisture into the system. Turn on the defrost and it actually heats up the system to draw the moisture back out instead of cooling the air and surface. On the right track Bob.
 

DGatzby

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#6
Hick, windows in Florida generally have condensation on the OUTSIDE. That is because the dew point of the air down there usually is in excess of the mid-70's, especially in the summer months. When the AC is running in the summer people keep the temps mid-70's or below. Cheap glass without much insulating property sweats on the outside. Because the temperature of outside of the glass is below the dew point of the outside air. At that dew point temp and lower condensation forms on the outside.

If your windows are sweating inside a vehicle, generally it will be in the cold climates. To make it happen, some people put their car on recirc. Do that and your breathing and maybe some fresh coffee, and you manage to raise the dew point inside the car. When cold outside the temp of the car glass can be below the dew point in the car and the inside windows steam.

Eliminate it by warming the air inside the car, or even opening the window or of course stopping the recirc and flipping it to flow through ventilation.

The use of the front defroster will generally clear the windshield is because that air is generally hot enough to WARM the inside of the windshield and in some cars it blows in the top/side vents to help clear the side windows also.
Also heating cold air will drop a dew point. In the summer, condensation is forming around the chilling coils of the AC system, thus the car passes water under and all over us motorcycle riders! If you are steaming the inside of the window or maybe the outside of your car window in the summer, you may be directing just too much cold air at a small area.

The OP does describe normal function. That is; the system blows either hot or could be cold depending on the demand from the temperature sensors inside the vehicle.
 

DGatzby

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#7
Bob, from Riverside Cal, you are on the mark, but to go a step further, add a dew point sensor. A step above the humidity but to measure the exact moisture in the air. There is a misconception of umidity and dew points. I have measurements in each room in the house that reads both. Been in the systems for a couple of years. That is why the chiller killer does not do all it is made to do. One system blows on and off where one as a mixing valve that will control the temp, humidity, and dew point not just to dump cold air in the system. That can actually make the system worse. Walk into a store and the windows are fogged up with moisture?? Dumping too much cold air but not lowering the dew point. It is raising the dew point adding more moisture into the system. Turn on the defrost and it actually heats up the system to draw the moisture back out instead of cooling the air and surface. On the right track Bob.
Dude, you have some special home if you have different dew points and/or humidity levels in each room!
 

Hickster

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#8
Yes sir,
By recirculating the moist air across the cold lines will normally drop the RH down to defrost, as they say, but when the thermostat is dropped to low it will increase the moisture content of the inside air. When the moisture content builds to the point of build up, the dew point is too high which doesn't matter what the RH is. Always tell by the build up on the glass. You can have an insulation factor of R20 but if recirculation and dew point is off line your defrost will not work properly. I don't drink hot caffeinated or not, but the build up will still happen especially in Fl. Return air is the proper method of reducing the problem.
 

Hickster

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#9
These levels can be changed by a method of a vav box industry called. Variable air volume box. Constant pressurized air with a thermostat in each room which they call residential uses now days, ductless air systems. as been in the commercial usage for 35 years. Stupid system in residential but in the commercial usage where you have different sized rooms and glass facing in different directions of the sun, make up for different heat and dew points. This can be regulated by your placement of your return air diffusers. Close to the glass or away from the heat source. Usually closer to the heat source, glass, will delete the sweating glass taking the hot condescended glass dry. In a large room 2 diffusors would be adequate 1 by the window and 1 by the exterior door to pull cool dry air from a neutral area,, hall way if the balancing of the system is correct or you are going to get a whistling affect. Which can be controlled by adjusting the return louver open or closed. Each room can be controlled by the amount of air forced into the room since it is not necessary the tempture of the air but the amount of air across the skin. This can be controlled by a VAV box to open and close a damper to regulated the air flow or a 3 way valve to regulate the amount of chill water and or refrigerant across the coil. Difference in regulation of chilled water can be determined between a two way valve and a 3 way valve. Hope this has educated and bored as many people as possible.
 

DGatzby

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#10
Yes sir,
By recirculating the moist air across the cold lines will normally drop the RH down to defrost, as they say, but when the thermostat is dropped to low it will increase the moisture content of the inside air. When the moisture content builds to the point of build up, the dew point is too high which doesn't matter what the RH is. Always tell by the build up on the glass. You can have an insulation factor of R20 but if recirculation and dew point is off line your defrost will not work properly. I don't drink hot caffeinated or not, but the build up will still happen especially in Fl. Return air is the proper method of reducing the problem.
You have to have an R-factor of 20 for what?

Tell me how blowing hot air across a windshield on a cold morning won’t tear the hell out of any interior condensation again??

Shit I have ripped that pussy frost off the exterior you guys get down south with a defroster, fluid and wiper, usually embarrassing the locals.

If you have so much moisture in that system and it won’t happen, you got other problems my friend.

So a build up of what in FL? Condensation inside or outside? I am in.

How does this relate to the OP’s perception of the normal air temp function of the HVAC System again Hick? I don’t think a humidity sensor is a problem at all obviously. I have owned about ten FCA systems like he describes including the two fine machines in the garage. Mine all work that way.
 

DGatzby

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#11
These levels can be changed by a method of a vav box industry called. Variable air volume box. Constant pressurized air with a thermostat in each room which they call residential uses now days, ductless air systems. as been in the commercial usage for 35 years. Stupid system in residential but in the commercial usage where you have different sized rooms and glass facing in different directions of the sun, make up for different heat and dew points. This can be regulated by your placement of your return air diffusers. Close to the glass or away from the heat source. Usually closer to the heat source, glass, will delete the sweating glass taking the hot condescended glass dry. In a large room 2 diffusors would be adequate 1 by the window and 1 by the exterior door to pull cool dry air from a neutral area,, hall way if the balancing of the system is correct or you are going to get a whistling affect. Which can be controlled by adjusting the return louver open or closed. Each room can be controlled by the amount of air forced into the room since it is not necessary the tempture of the air but the amount of air across the skin. This can be controlled by a VAV box to open and close a damper to regulated the air flow or a 3 way valve to regulate the amount of chill water and or refrigerant across the coil. Difference in regulation of chilled water can be determined between a two way valve and a 3 way valve. Hope this has educated and bored as many people as possible.
So, that is a description you must of cut and pasted of a rudimentary building HVAC system. I am bored. I actually hold our firm's General Contracting License in Florida. I can build from a home to anything you can dream up sir. That did nothing to help the OP Hick.
 
OP
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Thread Starter #12
I know this is an older thread, but I had similar issues in my 15 HC Charger.

I replaced the humidity sensor, up by the rear view mirror and haven't had a problem since.

Others have reported this, on LXForums and this also solved their problem.

It isn't cheap, at about $80, but it fixed our issues and they haven't come back.

My car had a code set, but not a light. It also did not show up, with the on board diagnostics. I used AlfaOBD to scan my BCM and found it lurking.

Replaced the sensor and cleared the code. No more issues, since early summer, 19.

Bob
Riverside, California
1) This is NOT an older thread, this is a thread that I have been waiting for the "Cares" team to respond to. (But I get what your saying) It has the @DodgeCares so I dont know why they haven't responded, I was just going to leave this up to see how long it takes them to respond.
2) That is the most awesome information on this issue I have seen to date. I am going to screenshot this and take it to the dealership and make them replace it and see what it does. I will update once I do this. Right now car is at the shop getting a few things fixed, like the heated steering wheel not heating up.
 
OP
SpecOps Veteran

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Thread Starter #13
Basically, when it's cooler outside 50 ish, or downright cold 10-40 ish, when I set the temp to blow at 68 or so it just goes all over the range of 80-180 whenever it wants like it has a mind of its own. I am a hot blooded individual so I want the air to blow around 68 but it just wont do it. Its extremely aggravating.
 

Diboblo

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#14
Basically, when it's cooler outside 50 ish, or downright cold 10-40 ish, when I set the temp to blow at 68 or so it just goes all over the range of 80-180 whenever it wants like it has a mind of its own. I am a hot blooded individual so I want the air to blow around 68 but it just wont do it. Its extremely aggravating.
When you scan the car, look for code P1009, specifically. It's callout specifically says not to set a light, but the code is present, in the background.

Also, I recommend EVERYONE pick up an OBDLink MX, or MX+ (if you have e an Iphone). The scan utility is very robust and is free, with the device.

Bob
Riverside, California
 

DGatzby

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#15
So it is attempting to make it 68 in your compartment. So when it is real cold it will blow hot until some mystery sensor says otherwise. It is a pain up here on a -20 day. The system won't pump out hardly any air , so it will steam up. We often need to just increase the fan speeds. But these automatic systems are trying to do a lot, I think. We usually override the auto with at least a min fan speed that makes sense. I know it blows different temps. Sitting in a GC now! Set at 72 degrees, it is 36 out, it feels like cool air coming out the vents, but we are comfortable.
 
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#16
1) This is NOT an older thread, this is a thread that I have been waiting for the "Cares" team to respond to. (But I get what your saying) It has the @DodgeCares so I dont know why they haven't responded, I was just going to leave this up to see how long it takes them to respond.
2) That is the most awesome information on this issue I have seen to date. I am going to screenshot this and take it to the dealership and make them replace it and see what it does. I will update once I do this. Right now car is at the shop getting a few things fixed, like the heated steering wheel not heating up.
Hi SpecOps Veteran, sorry to hear of the trouble you are experiencing. As our team here is not mechanically trained, we are unfortunately unable to speculate regarding vehicle concerns. However, if it would be of interest, we can connect you with a specialist for an extra layer of support as you address your current concerns with your dealer. We are just a PM away.
Rob
DodgeCares
 

SilverBillet

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#17
There you go! Help is here. Now you know to just take it to your dealer....(y):rolleyes:
 
Last edited:

SilverBillet

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#18
Sometimes mine blows hot when I don’t want it to. I believe it’s sensing that the outside temperature is cold and wants to give me heat. I just put it on auto air and close my vents. Sometimes it is blowing a mix of (cool) air to regulate the temperature when I really want heat. I usually can get hot air to come on by jacking the temperature up. Mostly, I think it is working the way it was designed by computer and sensors but I often miss the old manual temperature and fan controls.
 

Av8ing1

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#19
So, would it be accurate to say when you set a temp, say 70 the temperature at the vents will not be at 70. It will be significantly higher or lower as needed in order to bring the cabin to the selected temperature, measured by an ambient sensor. Thus duct temperature means very little.
 

stonewall

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#20
Basically, when it's cooler outside 50 ish, or downright cold 10-40 ish, when I set the temp to blow at 68 or so it just goes all over the range of 80-180 whenever it wants like it has a mind of its own. I am a hot blooded individual so I want the air to blow around 68 but it just wont do it. Its extremely aggravating.
I don't think any Dodge product will blow 68* air just because you set your temp setting to 68*. It will blow hot air until the temp in the cabin is 68* and stop blowing when it gets there. You are asking a lot of an AC system to perform as you describe. Some high end cars can, but not a Dodge. The system as designed will maintain the temp as you set it. The split system controls we have do more for air delivery than temp control.
 


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