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Nick's new Ram 2500

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2025 4500/5500

No heat in cab

The tag says R134a, 1.31 lb. Seems like a small system?
There seems to be a lot of complaints on the '19-'20's, not much on the '21 yet that I found. This quote is from another forum on a '19.

"Update:
I took my truck to a different dealership and asked them to evaluate my AC with the idea that the TSB would be a solution. The tech checked and the TSB did not apply to me. He verified that the A/C out of the vents was too high. It was coming out at 62F. The selling dealer told me the temperature was within spec. The new dealer vacuumed out the system, weighed it, and found it 1 lb low. He did not find a leak. He refilled the system with the correct amount of Freon and suddenly it is down to 52 degrees. We took the truck to Las Vegas the next weekend and the truck was much better."
Your quote of the underhood sticker and this persons update don't jibe.
If a system that only holds 1.31 pounds of refrigerant was low by a pound, it wouldn't even kick the compressor on.

But, anyway, I still say get an independent shop to hook their gauges up and see where it is at.
 
Your quote of the underhood sticker and this persons update don't jibe.
If a system that only holds 1.31 pounds of refrigerant was low by a pound, it wouldn't even kick the compressor on.

But, anyway, I still say get an independent shop to hook their gauges up and see where it is at.

Agreed, something is off with the numbers.

The sticker on my 14 says 1.37 lbs for 1500 and 1.19 for 2500 and up. Even if they upped the system capacity a pound low seems excessive. Typically takes 1/3 of system capacity to satisfy the low pressure switch.
 
Your quote of the underhood sticker and this persons update don't jibe.
If a system that only holds 1.31 pounds of refrigerant was low by a pound, it wouldn't even kick the compressor on.

But, anyway, I still say get an independent shop to hook their gauges up and see where it is at.

Yes, I saw that discrepancy. My son said he would be glad to pull it down and refill it. He said he uses the gauges to show full, not the oem's listed capacity.

He also said it might be an electronic issue and not mechanical. That maybe the computer sees the -40 degree below ambient and shuts off the compressor or opens the blend door slightly. That if the computer is reading the A/C temp control but the vents are warmer, the blend door may be at fault or that the hot heater core is just too much for a marginal system to overcome and might never be improved on.
 
the blend door may be at fault or that the hot heater core is just too much for a marginal system to overcome and might never be improved on.

You can get a fairly good idea of whether or not the blend door works by checking the heater hoses at temp and check the temp of the fan blowing with A/C off, temp turned to cold, fan on high. Should be ambient.
 
You can get a fairly good idea of whether or not the blend door works by checking the heater hoses at temp and check the temp of the fan blowing with A/C off, temp turned to cold, fan on high. Should be ambient.

Just checked it @ 70 ambient, the vents are 78:(
 
Was your truck in the shade Nick?
If it's been sitting in the sun and is heat soaked it can skew the numbers a bit.

It is in the sun but I had it running for a while, messing with my cell and bluetooth. Also the coolant was only 140. I will try the test again when at operating temps.
 
It is in the sun but I had it running for a while, messing with my cell and bluetooth. Also the coolant was only 140. I will try the test again when at operating temps.
I’d recommend checking the temps whilst driving and compare the numbers at idle with numbers while driving. Lots of difference in airflow while driving. In any event....you’ve established that it’s probably low of R134a.
 
Guys, I'm no AC expert, but all the Rams I've owned would freeze you out...93 to 2017 diesels, 2019 gasser, 2014 Jeep Wrangler, and 78 LRE, and 2020 MH will freeze you out. Max cold AC on the MH keeps cab and front area of RV cool. I don't understand these issues on these trucks. Cold AC is a necessity in SW US or anywhere. My 2017 Ram 5500 reads 48° at the vent... keep AC thermometer in it. Need one in MH too.

Anyhoo, sorry for the rant. Cold AC is a must.

Stay comfy, Ron
 
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I’d recommend checking the temps whilst driving and compare the numbers at idle with numbers while driving. Lots of difference in airflow while driving. In any event....you’ve established that it’s probably low of R134a.

You are correct. I hauled 4 loads of demolition concrete yesterday and had time to mess with the a/c. At 197 operating temp, a/c off, fan on 3/4's, ambient 81 degrees the vents were 91. At 95 ambient, a/c on, 3/4's fan, 197 coolant temp, vents were 52. Both times I was cruising down the highway. The higher the fan speed the better it works.

What do these new trucks weigh? I think I read somewhere my 2500 is 7600 lbs empty but that must be without options. I was at 15,120 with my light dump. My '01 with the same trailer is at 14,300. I have less extra weight in the new v/s the '01.

Loads were 5, 5.2, 7 and 9 ton. The last load we didn't want to split it and make two, so I hauled it:eek: His crew hauled 3 loads with his small dump. Have I said I really like this new truck?:D

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So with you moving the difference between outside ambient temp to cabin air flow is more, not less, than stationary.
No good!
 
So with you moving the difference between outside ambient temp to cabin air flow is more, not less, than stationary.
No good!

Yes, what I was afraid of, all along. Heater core heat, contaminating the evaporator, typical Dodge/Ram.
 
If you had the Fu Fu package :D you could get it recalibrated and maybe see an improvement....

As much as it stinks doing to a new vehicle Mike had the solution a while back.
I had to do it to my Vee Dub a few years ago. But only because I didn't feel like tearing the dash apart to fix a blend door issue...NOT because the system was subpar right out of the box....
 
What do these new trucks weigh? I think I read somewhere my 2500 is 7600 lbs empty but that must be without options.

The brochure weight for your truck is 7507.

If you take the GVWR and subtract the payload on your door jamb sticker you will get what your exact truck weighs.
 
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