Why is the air conditioning so bad in a 2019 Ram 3500?

Update:
The dealer installed a fix which worked. If you want more details, read these posts that I made.
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hdrams.com/for...
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Many people have been complaining about insufficient air conditioning cooling in the 2019/2020 Ram 2500/3500.
One theory [that wasn't my idea] is that hot coolant always flows through the heater core inside the cab, so the air conditioning is fighting the heater core.
I decided to test this theory by installing a valve in the heater core loop. The valve lets me stop coolant from flowing through the heater core.
I used 4 digital thermometers to measure the temperature of all 4 vents. I set climate system to LO with recirculation enabled, and then I monitored the vent temperature every 30 seconds along with the engine temperature.
I observed the vents quickly reached their lowest temperature while the engine was still getting warm. As the engine got warmer, the driver's right vent increased by 3 degrees (F).
Once the engine reached thermal equilibrium at 188 degrees (F), I closed the valve to block coolant from entering the heater core. Immediately the vent temperature started dropping, especially in the driver's right vent. Very quickly, the driver's right vent dropped by 7 degrees.
I opened the valve to allow coolant to flow through the heater core. Very quickly, the vent temperature increased.
Again, I closed the valve to block coolant from flowing through the heater core. Very quickly, the vent temperature decreased.
Again, I opened the valve to allow coolant to flow through the heater core. Very quickly, the vent temperature increased.
I believe this experiment definitively proves that hot engine coolant always flows through the heater core which significantly reduces the effectiveness of the air conditioning.
The solution would be for Ram to insert a valve to restrict the flow of coolant to the heater core when not required.
I apologize for the pollen on my center console screen. I swear I cleaned it less than a week ago, but it is pollen season where I live.
Separately, there is another theory [proposed by hdrams member g00fy] that the air conditioning sensors are not configured properly. I will test that theory in another video. An early investigation seems to confirm there is a problem with the A/C sensors.
If you want to contribute either investigation, please go check out these topics on the hdrams forums.
Fix for A/C issue??
www.hdrams.com...
Constantly adjusting heat
hdrams.com/for...
A/C Issues? Anyone else
hdrams.com/for...

[@alstuart]

Ram released a fix for this issue in TSB 24-001-20 in November, 2020.

[@nandiito]

What is the fix or where can I read about it?

[@alstuart]

@@nandiito Google "TSB 24-001-20" and read the first document. The Fix is to have the dealer replace some air conditioning components. It was free for me because my truck is still under warranty, but it may not be free if your truck is out of warranty.

[@nandiito]

@@alstuart I just got a 2021 TRX, not sure if it would have that problem but I’ve been in the forums and seeing people complain about their ACs. Not sure if mine has that problem.

[@alstuart]

@@nandiito TSB 24-001-20 only applies to 2019 and 2020 models. There may be a separate issue with the 2021 models, but I am not aware of it. I recommend you take it to the dealer so it can at least be logged. Sometimes Ram doesn't take an issue seriously until enough people have complained.

[@jjpjjpjjp1]

I am realizing that i need this fix done

[@socal33]

The Muzzy's mod has definitely made a difference in my '20 Ram 1500. Much colder, measured with thermometer.

[@tratzum]

Spot on! I live in Central Texas and have a 2019 ram. The AC was instantly noticeably shitty. When summer reared its head. Long hauls it was ok..but city driving in this truck is crazy. Dealership won't do anything since it's "working as intended "

[@bman1655]

I am having the same issue, very frustrating!

[@RK-hp2hr]

@Steven Ellis Ram released a TSB to fix this issue. 5thgenrams.com/community/threads/a-c-performance.605/post-364641

[@rjterry21]

Very well done Alan.

[@josephpuchel6497]

Hey I have same issues I’m calling stealership for the TSB fix. Excellent video

[@XD65]

Awesome video. Appreciate it. Will be doing.

[@JerryLee..]

Send this to Ram engineering. Lol

[@alstuart]

I don't know if anyone at FCA saw this video, but they fixed this in November, 2020. See TSB 24-001-20.

[@codtrend8868]

ElectroBoom joined the chat

[@khakiswag]

Well done test. But since the previous models also had coolant constantly through the heater core yet had colder air, it doesn’t explain the weak performance. From what I understand the refrigerant capacity on the new model isn’t much, like 1.2 lbs. Is this the same as the previous model?

[@alstuart]

Ram released a fix for this. I had the repair done on my truck. They had to replace a HVAC control module and two major HVAC ducts that reroute the coolant lines. At least I got a free coolant change out of the repair!

[@bradwilliams7550]

@@alstuart Was the repair effective? Can you quantify it? Thanks!

[@alstuart]

@@bradwilliams7550 I wrote a review of the results on hdrams dot com forums in post #55 and #58 in the thread titled " Constantly adjusting heat." I will edit the video description with links.

[@FXTdriver]

Hey Alan, g00fy here, excellent video man, would you be able to make a video like this that shows the erratic behavior we believe is caused by what we suspect is screwed up software values?

[@alstuart]

I am on a long road trip. I will upload a video as soon as I get back. It maybe about 4 weeks. Sorry for the delay.

[@josephpuchel6497]

Hey I believe the temps will get colder if engine increases RPM. When i had my 2019 Ram at dealership the mechanic indicated that the engine RPM has to be at 1500 to test system.

[@sea0devil919]

I just tell the agency’s in kuwait about what you did at same time they cancel it for me the ac now its like Refrigerator

[@Neur0bit]

There’s a TSB out for this now. Fixes this exact issue: AC issues are a combination of the blend doors not sealing correctly (hence the reason for the new HVAC box part number), a duct temp sensor location (the reason for the new distribution box part number and new temp sensor), and HVAC module mapping (the reason for the new HVAC module part number). static.nhtsa.gov/odi/tsbs/2020/MC-10184475-9999.pdf Cheers

[@alstuart]

Thanks. I pinned a comment about the TSB.

[@hiimkalx]

Do you know how much this TSB will cost?

[@Neur0bit]

@@hiimkalx Wish I could help but IDK, since mine was done while under warranty and TSBs are covered. Otherwise, you will need to ask dealer for pricing. Tell you what, the amount of work involved is extensive so it cannot be cheap. Thanks.

[@alstuart]

@@hiimkalx It didn't cost me anything when my dealership performed the repair in the TSB. If your dealership refuses to perform the service, let me know so I can help you.

[@hiimkalx]

@@alstuart yeah they said they can’t give me a price because I need to take it in. So I did and then they told me that my expansion valve is the problem. Is your truck still full bumper warranty? Mine has 50K miles on it and I only have the power train warranty left. I also have a 2019 2500 Cummins.

[@dmtycn]

They build a machine but bad HVAC, pity!

[@chrisbryan6493]

I have a 22’ with 1k miles.. A/C is sub-par.. my 07 Cadillac blows way colder..

[@Joe.O_623]

Did the dealer ever take care of this? I have a 22 with the same problem.

[@makefitdepartment8621]

Just curious, does RAM have any kind of valve in the heater loop and if so, where is it located?

[@ltjorge16]

Does this effect happen on the 1500 as well?

[@alstuart]

The TSB does apply to MODELS: 2019 - 2020 (DT) RAM 1500 Pickup

[@RK-hp2hr]

Ram released a TSB last week to fix this issue. 5thgenrams.com/community/threads/a-c-performance.605/post-364641

[@dmtycn]

Did you record how to install that valve?

[@alstuart]

I didn't record a video, but it is really simple. Just cut the heater core outlet hose about 4 inches from the end closest to the front of the truck. Install the valve inline and clamp.

[@dmtycn]

@@alstuart Do you close the valve for better AC or keep it open?

[@dmtycn]

I just found Ramcare post on forum that they are developing a solution to solve this problem, waiting!

[@mansour3250]

@@dmtycn Great news, I can't thank you enough George C

[@alstuart]

@@dmtycn Which forum? Thanks George!