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Fix for A/C issue??

thestuarts

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Did they happen to give any specs on the valve in regards to size and operating temperature range?

The size of the connectors is for 5/8" heater core hose. I will ask them about the operating temperature range of the coolant and the ambient operating temperature.
 

2019_Ram

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With regard to size, I was actually talking about the physical size of the valve. It seems with these newer trucks we don't have an overabundance of space to work with.
 

thestuarts

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With regard to size, I was actually talking about the physical size of the valve. It seems with these newer trucks we don't have an overabundance of space to work with.

Ah, I see. I will ask.

This is what they said about the temperatures:

These heater control valve are designed to be used in standard cooling systems 195°-220°
It doesn’t give a rating for the ambient spec but it will handle normal underhood temps, just try to keep it away from high heat sources.
 

Burton12387

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Here’s a quick test I did today in the driveway, as this has been bugging me. Not looking too forward to 90-100 degree days....this problem stacked on top of some other annoyances, this might be my last ram. I have 0 faith a trip to the dealership will solve anything, so, probably won’t waste my time. Maybe look harder into this heater core bypass.

40864bad4847fe534f55b44a71a45087.jpg



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Gondul

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Here’s a quick test I did today in the driveway, as this has been bugging me. Not looking too forward to 90-100 degree days....this problem stacked on top of some other annoyances, this might be my last ram. I have 0 faith a trip to the dealership will solve anything, so, probably won’t waste my time. Maybe look harder into this heater core bypass.

I will tell you right now the dealer will tell you the AC system is working within spec... never mind that the spec sucks, but that is what they are going to tell you... same thing they are telling the folks with 1500s.
 

RainDesert

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Here’s a quick test I did today in the driveway, as this has been bugging me. Not looking too forward to 90-100 degree days....this problem stacked on top of some other annoyances, this might be my last ram. I have 0 faith a trip to the dealership will solve anything, so, probably won’t waste my time. Maybe look harder into this heater core bypass.
My 2 trips to the dealer netted nothing really. I was pretty tempted to do the bypass as that is the only real fix out there. But then the blend-door issues just pushed me back to Ford. Now I have a perfect HVAC system and don't need to run AC on 60 deg. days anymore. While I would really like to be in a 6.4 and 8spd I just can't put up with the other stuff. Hopefully Ram gets this figured out and puts the 1500 cab on the HD, then I could be looking at Ram again.
 

thestuarts

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I ordered the Vintage Air 461171 Heater Valve and will be installing it inline with the heater core inlet hose and connect it to an AUX switch. I will measure the vent temperatures with the valve open and closed. Wish me luck!
 

Burton12387

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2019_Ram

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I've got several things ordered that should be here this week. When I get them, I will post some pictures to show my thought process more clearly.
 

Burn'n Oil

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I posted the following in another thread, but thought it may be helpful here.

Decided to take the plunge today and temporarily bypass my heater core. 2019 2500 6.7l diesel. There was a significant difference in the performance of the A/C and its ability to cool the cabin.

Before the temporary bypass I was seeing on average 56* vent temps with an outside temp anywhere between 60*-80*.
Bypass installed today, I was seeing 43-44* vent temps with an outside temp of 86* and ALFAOBD showing an EVAP temp of 37-40*.

A 12* vent temp difference is very significant and makes a very noticeable difference in the amount of time the cab takes to cool down. It is unacceptable to be hacking a valve in the cooling system of an $80k truck, just to have adequate A/C performance. Anyone else want to take the plunge and temporarily bypass your heater core in the pursuit of adequate A/C? And is there any speculation as to why RAM is unable to come up with a simple solution of using a small 12v coolant shutoff valve and a little programming to make it work seamlessly with the HVAC system?
A more intriguing question is: Why do many of these trucks have a HVAC system that performs well? This mbr's Dodge has been set to 'Auto' for a year and heats just fine near -40 and cools quite nicely at 90 degrees. Ack the ingenuity in hacking the system to make it more or less function, but that doesn't resolve the issue of why some work and too many others, don't.
 
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Gondul

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A more intriguing question is: Why do many of these trucks have a HVAC system that performs well? This mbr's Dodge has been set to 'Auto' for a year and heats just fine near -40 and cools quite nicely at 90 degrees. Ack the ingenuity in hacking the system to make it more or less function, but that doesn't resolve the issue of why some work and too many others, don't.

Someone suggested dual zone vs single zone, but I don't think that is the sole reason.
 

orlando bull

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Someone suggested dual zone vs single zone, but I don't think that is the sole reason.

Just a point of reference, I have the dual zone, mine seems to work pretty good. No scientific data or measurements, but, it was about 92 yesterday, my driveway is on the south side of the house, so, truck in full sun. Started it maybe 3 min before leaving the house, and by 5 min after I was driving, it was good inside. My only issue is that I have twins in rear-facing seats and they get hot because there isn't good flow in the back for them. I have a fan on order to get more air to them. My nearly 4 year old will be cold because she is facing the vents and the poor babies are hot. Wish the vents were overhead.

It is extremely odd that there is such a variance between different trucks.
 

2019_Ram

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I guess you could say, I only have the HVAC issues half of the time. My issues are only with the A/C, which has never felt adequate since owning the truck. Being how I picked the truck up in August of last year, there wasn't too much of hot weather left for me before winter set in. The heat gives me absolutely no complaints and the truck warms up quickly.

On a recent drive after spending a bit of time sitting in the sun, the truck had an interior temperature of 123* starting out, 95* after 10 minutes, and 74* after a 50 minute drive. Outside temperature was 78*. Interior temperature was measured on top of the center console, and the vent temp never dipped below 55*.

Earlier that morning, it came out of a 76* garage and took 14 minutes to get the interior temperature to 70*

On a different note, it seems a Longhorn 2500 Diesel takes about 65amps after starting to run the truck without grid heaters or batter recharging. A/C on, radio on, and daytime running lights on.
 

Jimmy07

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Someone suggested dual zone vs single zone, but I don't think that is the sole reason.
I believe it is, and if it isn’t, then there is two different issues going on between the two systems. If we want to figure this out, then we need hard data from the HVAC module, not a bunch of “I live here in this climate, and mine is or isn’t fine”, because everyone “feels” temperature differently. 70* to me is like hell, where 70* to my wife is like an icebox.
The single zone MTC just uses a blower motor with different speeds, two blend doors, and the evaporator with it’s temp sensor. If you’re set all the way on cold, then the blend door should be shut and sealed, and the air coming off the evaporator should never see the heater core. So, with the single zone, if you’re set all the way cold, the HVAC module is reporting 36* from the evaporator, and you’re shooting 50* with a temp gun at the vents, then you have a blend door sealing issue.
With the dual zone ATC system, now you have the outside air temp, the cabin temp sensor, a different sun sensor, and four in duct temp sensors that all come into play on how the HVAC module controls the climate. @g00fy has pulled some data logs, and it seems there’s a few weird readings going on. The cabin temp sensor seems to be reporting the temp that the climate controls are set at, not the temp of the air around it. This alone would explain the majority of the issue.
All we need is for a few more people with dual zone ATC that have AlfaOBD to data log some temps. Mainly the cabin temp vs the climate temp setting, and how it reacts when 1) the climate setting temp is changed, and 2) when the air temp around the cabin temp sensor is changed with a hair dryer. Then we can start picking up a pattern. But, every time @g00fy suggests this, it always gets sidetracked to “adding a valve to bypass the heater core”, which is not a solution. If everyone does this, then nobody at FCA will know there’s an actual HVAC programming issue. If we get enough hard data on the temp sensors, then “someone” with FCA can be alerted- “hey, these temps sensors are giving bad info”, and that’s the only way TSBs get put out for software updates.
 

thestuarts

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I believe it is, and if it isn’t, then there is two different issues going on between the two systems. If we want to figure this out, then we need hard data from the HVAC module, not a bunch of “I live here in this climate, and mine is or isn’t fine”, because everyone “feels” temperature differently. 70* to me is like hell, where 70* to my wife is like an icebox.
The single zone MTC just uses a blower motor with different speeds, two blend doors, and the evaporator with it’s temp sensor. If you’re set all the way on cold, then the blend door should be shut and sealed, and the air coming off the evaporator should never see the heater core. So, with the single zone, if you’re set all the way cold, the HVAC module is reporting 36* from the evaporator, and you’re shooting 50* with a temp gun at the vents, then you have a blend door sealing issue.
With the dual zone ATC system, now you have the outside air temp, the cabin temp sensor, a different sun sensor, and four in duct temp sensors that all come into play on how the HVAC module controls the climate. @g00fy has pulled some data logs, and it seems there’s a few weird readings going on. The cabin temp sensor seems to be reporting the temp that the climate controls are set at, not the temp of the air around it. This alone would explain the majority of the issue.
All we need is for a few more people with dual zone ATC that have AlfaOBD to data log some temps. Mainly the cabin temp vs the climate temp setting, and how it reacts when 1) the climate setting temp is changed, and 2) when the air temp around the cabin temp sensor is changed with a hair dryer. Then we can start picking up a pattern. But, every time @g00fy suggests this, it always gets sidetracked to “adding a valve to bypass the heater core”, which is not a solution. If everyone does this, then nobody at FCA will know there’s an actual HVAC programming issue. If we get enough hard data on the temp sensors, then “someone” with FCA can be alerted- “hey, these temps sensors are giving bad info”, and that’s the only way TSBs get put out for software updates.

I can (and planned to) do the AlfaOBD logging, but I think it's also valid to test the bypass valve so as much information as possible can be given to someone at FCA. For example, I can get AlfaOBD logs with the bypass valve open and closed to see if it is a factor.
 

thestuarts

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With regard to size, I was actually talking about the physical size of the valve. It seems with these newer trucks we don't have an overabundance of space to work with.

The electronic valve dimensions are
4.5”L x 3”H x 2.5”W
 

2019_Ram

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I'm still waiting on my pieces to show up...

As for the logging, I will most likely work on it at some point in time, but am not overly optimistic that RAM will make a change in any sort of reasonable time. I have been to the dealer a number times to voice my displeasure with the a/c performance. They run the cool down test per RAM, and it passes so that is all the troubleshooting RAM allows then to do. "Working as designed...". With the larger number of a/c complaints, including those in the 1500's, RAM could have more data then they could handle it they allowed the dealers time to look, record, and report it to them, rather than saying only an issue if it fails the cool down test. My dealer has been very good to work with, but they are very limited in what they are able to do without adequate direction and support from RAM.

The valve is my focus because it is something I can install and control myself. It will make an immediate and noticeable difference instead of being at the mercy of a headless corporation. Even if we were do identify a programming issue, we would still be at their mercy for them to acknowledge their failure and administer an appropriate fix.
 

2019_Ram

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Could you help show me a better picture or highlight the area you are talking about the small section of hose and valve to be installed that you were discussing in the link?


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Well, I got the valve picked up today. Here are a few pictures to show my thinking... This will hopefully pop into the coolant connector leaving the head and then the heater inlet pipe will connect to the open end. I had hope the valve would have been a little smaller, but I think it will still fit without issue.
 

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