Ac blowing from the defrost in all modes...

[Albert193500]

Hi All,

I am posting this concern from Thursday 9/12/19.

My 2019 3500 is having an issue where the AC is coming from the defrost in all modes. To clarify, when in vent mode it seaps from the defrost and constantly fogs up the windshield, the longer i sit or drive the worse it gets. If I turn the wipers on it gets worse much faster. If I put it in foot mode it is substantially worse.

I took it to the dealership and they have a case open due to it being a safety concern but told me that FCA is aware of the issue and there is nothing the can do. It was suggested to put a mat over it or rainx it. I have already rainx it. On the way to and from North Carolina I had to stuff clothes between the dash and windshield in order to drive at night. I checked 3 other trucks on the lot and they all did the same thing. This is a serious safety issue since I live in Florida and the humidity is always through the roof. My local dealer also did a recalibration of all mode doors and modules. There was no improvement at all.

Has anyone found the issue or had any success in a repair?

 

[Albert193500]

Update 9/17/19

I got a call back from FCA. As expected, they claimed it was operating as "designed". I stated, as a 25 year mechanic and ASE certified, I will not accept that answer. I can not accept that Ram designed a truck to blow air from the defrost in all modes and fog the windshield while a vehicle is in motion. I can not accept that a truck rated to tow 30k pounds down the same highway as a school bus can obstruct half of the windshield in a night or early morning commute. Nor can I accept that the answer given to me by the service department was to put a rag, dashmat, or other obstruction to further block my view. I am not upset but very concerned, I tow a large 5th wheel with my wife, 2 kids, and a dog. I do not want to be a statistic for the NHTSA or the reason to fix the problem after an accident.

The problem I discovered is that as long as the service department is putting " Could not duplicate, system is operating as designed" on the paperwork they do not have to recognize it is a major safety problem. So I will be heading back to the dealership to report the problem again and this time I will not accept the paperwork with those lines on it. It needs to say something to the effect, air is blowing out of the defrost vent in all modes. I will not accept the paperwork if it says "could not duplicate" or "system operating as designed".

The lady I was speaking to was very understanding and kind, so I am not being negative but just documenting this for myself and others.

 

[Gondul]

This has been an issue since the 2019 1500s rolled out last year... along with inadequate AC performance.
I can't say the AC isn't working because FCA states it is operating as designed...

 

[Albert193500]

This has been an issue since the 2019 1500s rolled out last year... along with inadequate AC performance.
I can't say the AC isn't working because FCA states it is operating as designed...

Right, as long as we accept the wording on the paperwork it does not look bad to people in the corporate offices. It looks like a lot of people dont know what they are talking about.

 

[Distillusion]

This sounds like a mix problem. The best method of defrosting is to blow dry air (warm, of course) to help evaporate off moisture more quickly. A good defroster/demister mixes some A/C airflow with some heated air. It sounds like you're only getting half what you need.

 

[Gondul]

This sounds like a mix problem. The best method of defrosting is to blow dry air (warm, of course) to help evaporate off moisture more quickly. A good defroster/demister mixes some A/C airflow with some heated air. It sounds like you're only getting half what you need.

Most over on the 1500 board seem to agree it is a blender door issue and some have clamped the hose coming out of the heater core (I think I said that correctly) to make the AC colder.

 

[AndyS]

I would agree with that assessment. This morning was very chilly. Put the heat on halfway and wow did it get hot in the cab. Had to turn the knob to 2 clicks from max cold for it to be warm. I've also noticed that when a/c was on, if a turn a click or two from max cold, the air got warm real fast. So my thoughts this morning were that is was a blend door issue. Question is, is this an easy fix or adjustment? Is it the same system as the 2018's? If so, how hard to change it over?

 

[Albert193500]

My dealer claimed the did a recalibration and also claimed everything is operating as designed. I am a 25 year mechanic and I know it is BS.

 

[Gondul]

My dealer claimed the did a recalibration and also claimed everything is operating as designed. I am a 25 year mechanic and I know it is BS.

You know it is BS because you've seen and reviewed the 2019 RAM AC specs as published by FCA?

 

[Albert193500]

You know it is BS because you've seen and reviewed the 2019 RAM AC specs as published by FCA?

Actually I tried but you cant get any of that info yet. I cant even get part numbers yet for the actuators.
Its BS because there is no reasonable reason why you would want to blow cold air on the windshield. It serves no purpose. If it was warm air I might not call it bs. But if you have those specs i would love to browse through it, ijs.

 

[Jim Severence]

Actually I tried but you cant get any of that info yet. I cant even get part numbers yet for the actuators.
Its BS because there is no reasonable reason why you would want to blow cold air on the windshield. It serves no purpose. If it was warm air I might not call it bs. But if you have those specs i would love to browse through it, ijs.

The air conditioner will take moisture out of the air being circulated. So when the air is directed at the windshield, it will absorb the moisture that has collected on the windshield and therefore clearing up the windows.
The colder the air the less water vapor it can hold.

 

[Albert193500]

The air conditioner will take moisture out of the air being circulated. So when the air is directed at the windshield, it will absorb the moisture that has collected on the windshield and therefore clearing up the windows.
The colder the air the less water vapor it can hold.

I hear you, but my issue is not moisture on the inside of the windshield. The cold air constantly blowing at the base of the windshield is creating a layer of condensation on the outside of the glass creating a visibility concern. The end game here is to stop the flow of cold conditioned air to the windshield when not required. I know how to use the defroster and how the ac system works. I also know that it is not something that is designed into a vehicle because it creates a major safety concern (poor visibility out of the windshield).

 

[Jim Severence]

I hear you, but my issue is not moisture on the inside of the windshield. The cold air constantly blowing at the base of the windshield is creating a layer of condensation on the outside of the glass creating a visibility concern. The end game here is to stop the flow of cold conditioned air to the windshield when not required. I know how to use the defroster and how the ac system works. I also know that it is not something that is designed into a vehicle because it creates a major safety concern (poor visibility out of the windshield).
View attachment 1250

Ok, so the temperature of the windshield is getting below the dewpoint temperature. I have seen this too on a rare occasion, but I don’t live in a humid area so it doesn’t too often. Sorry for the confusion.

 

[Albert193500]

Ok, so the temperature of the windshield is getting below the dewpoint temperature. I have seen this too on a rare occasion, but I don’t live in a humid area so it doesn’t too often. Sorry for the confusion.

Correct, it "seems" to be a simple mode door problem. And the cooling issue is a blend door problem, this seems to be confirmed. I say that because of people clamping the heater core supply line and the problem is gone.

 

[Distillusion]

You would think clamping the heat supply would just make this particular problem worse. It would reduce hot water to the A/C for trying to cool the truck, but it would also prevent the defroster mix from warming the defroster air after drying it.

 

[Albert193500]

You would think clamping the heat supply would just make this particular problem worse. It would reduce hot water to the A/C for trying to cool the truck, but it would also prevent the defroster mix from warming the defroster air after drying it.

Not really, the blend door is not closing all the way causing hot air from the heater side to go in the evaporator side. By stopping the flow of hot coolant, the air on that side will be ambient temperature and cool as if there was no problem. It drops the ac temps by about 10 plus degrees or more.

The issue I have is I am not sure of the flow rate or direction on the Cummins.

 

[Distillusion]

Not really, the blend door is not closing all the way causing hot air from the heater side to go in the evaporator side. By stopping the flow of hot coolant, the air on that side will be ambient temperature and cool as if there was no problem. It drops the ac temps by about 10 plus degrees or more.

The issue I have is I am not sure of the flow rate or direction on the Cummins.

I think you're referring to the need for cooling the truck with the A/C. I was referring to the need to defrost with slightly warmer air. Slowing the heater supply fixes the A/C but breaks the defroster, then. The blend door definitely is needing to be fixed.

 

[Albert193500]

I think you're referring to the need for cooling the truck with the A/C. I was referring to the need to defrost with slightly warmer air. Slowing the heater supply fixes the A/C but breaks the defroster, then. The blend door definitely is needing to be fixed.

Yes, you are correct. That's why I am trying to fix my defrost issue before I attack the cooling issue

 

[Distillusion]

Yes, you are correct. That's why I am trying to fix my defrost issue before I attack the cooling issue

Here's a diagram and explanation I found from a forum, from an old Dodge service manual. It might help, if things haven't changed too much.

"The heating-A/C system pulls outside (ambient) air through the fresh air intake (4) located at the cowl panel at the base of the windshield and into the air inlet housing above the heating, ventilation and air conditioning (HVAC) housing and passes through the A/C evaporator (7). Air flow is then directed either through or around the heater core (2). This is done by adjusting the position of the blend-air door(s) (3) with the temperature control(s) located on the A/C-heater control in the instrument panel. Air flow is then directed out the floor outlet (8), instrument panel outlet (10) or the defroster outlet (1) in various combinations by adjusting the position of the mode-air doors (9 and 11) using the mode control located on the A/C-heater control. The temperature and mode control uses electrical actuators to operate the air doors.

The velocity of the air flow out of the outlets can be adjusted with the blower speed control located on the A/C-heater control.

The fresh air intake can be shut off by pressing the Recirculation button on the A/C-heater control. This will operate the electrically actuated recirculation-air door (5), which closes off the fresh air intake. With the fresh air intake closed, the conditioned air within the vehicle is pulled back into the HVAC housing through the recirculation air intake (6) located within the passenger compartment.

On models equipped with A/C, the A/C compressor can be engaged by pressing the A/C (snowflake) button on the A/C-heater control. It will automatically engage when the mode control is set in any Mix to Defrost position. This will remove heat and humidity from the air before it is directed through or around the heater core. The mode control on the A/C-heater control is used to direct the conditioned air to the selected system outlets.

The defroster outlet receives airflow from the HVAC housing through the molded plastic defroster duct, which connects to the HVAC housing defroster outlet. The airflow from the defroster outlets is directed by fixed vanes in the defroster outlet grilles and cannot be adjusted. The defroster outlet grilles are integral to the instrument panel top cover.

The side window demister outlets receive airflow from the HVAC housing through the molded plastic defroster duct and two molded plastic demister ducts. The airflow from the side window demister outlets is directed by fixed vanes in the demister outlet grilles and cannot be adjusted. The side window demister outlet grilles are integral to the instrument panel. The demisters direct air from the HVAC housing through the outlets located on the top corners of the instrument panel. The demisters operate when the mode control **** is positioned in the floor-defrost and defrost-only settings. Some air may be noticeable from the demister outlets when the mode control is in the bi-level to floor positions.

The panel outlets receive airflow from the HVAC housing through a molded plastic main panel duct, center panel duct and two end panel ducts. The two end panel ducts direct airflow to the left and right instrument panel outlets, while the center panel duct directs airflow to the two center panel outlets. Each of these outlets can be individually adjusted to direct the flow of air.

The floor outlets receive airflow from the HVAC housing through the floor distribution duct. The front floor outlets are integral to the molded plastic floor distribution duct, which is secured to the bottom of the housing. The floor outlets cannot be adjusted. "

 

[Albert193500]

Update after my appointment with the dealer...

After speaking with several members of this and other forums. I had the dealer try a thing or two. As of now I will just say this was not my idea. This is experimental at this time but we have at least one more truck being tested tomorrow. This is not a fix but a big step on the right direction. I will state my results as of tonight and tomorrow after I hear back from the other truck owner we can post what they did. As of now I have no discernable air coming from the defrost in vent mode. Once the foot mode is engaged it still comes from the defrost. Again it's not fixed but it is much improved. This small step makes it a bit safer to drive. I have not driven it at night as of yet, possibly tomorrow night I will take a trip for testing.

Also this proves it is not a design characteristic. I understand that things take time to fix and when you have a few thousand parts coming together to make one machine it is not always perfect. For me it is more about the way you handle the customer regarding their concerns then the amount of smoke you try and blow up my a$$.

With that all said, I will post my results tomorrow and go from there.