JimmyZ
Member
I haven’t been told about a factory fix but I found if I turn it down to LO and then back to 68 it blows colder (for a little while).
Last edited:
You describe my last 2019 2500 and current 2020 1500. 2 trucks in a row is not a fluke, the current system is a poor design.Welcome to Dodge HVAC. My '05 A/C was marginal, and would get warm in slow driving, as they didn't run the fan to cool the condenser. I was very fortunate to have avoided the dreaded blend door failures that ran rampant in the 3rd Gen trucks. Just google "heater treater". My wife's '06 Charger had the hot air infiltration problem pretty bad. My '15 2500 was a definite improvement in all aspects. Now, this '19 pretty much sucks. Hot air infiltrates and fights the A/C, even on Max Air it can barely keep up on a hot AZ day, it goes through some wild temperature fluctuations, and once in a while will blow scalding hot air out the driver's side vents. On Max Air with fan on HIGH(7) the A/C struggles to get down to 50, and rarely will get below that. On a cool morning, I like to run with the A/C off and just run the fan like selecting "vent" in the old days. With the temp selector set to LO enough hot air infiltrates the plenum that it will add about 15 degrees to the outside air. I run an A/C thermometer in my center vent, to the left of the radio just for this purpose. It is amazing to me that after all this time they still haven't figured out how to make an HVAC system for these trucks. As much as I don't like Ferd, and I stopped buying them because of major issues, I never owned a Ford that you couldn't "hang beef" in. They would put frost on the windows.
You describe my last 2019 2500 and current 2020 1500. 2 trucks in a row is not a fluke, the current system is a poor design.
It must be fixed in the 2020, my wife complains about how cold the AC is all the time when I'm driving and has a blanket by her feet she can pull up to stay comfortable.
What ever came of this? I retrofitted a 12" UAX into my tradesman with single zone climate control, added a cabin temperature sensor, and the ATC solar sensor, and I'm having a very similar issue. However since i have single zone blower system, instead of getting blazing hot air from just the driver side vents i get it from ALL vents and can't get cool air until i knock the system all the way down to low.
Recently AlfaOBD released an update to add support for the 2019+ Climate control system so i was able to go in and actually see what the system was doing to regulate the cabin temperature. I found something interesting, and I don't know if it's got to do with the fact that i retrofitted the system in, or if maybe there's a software glitch in the truck.
When I checked the real time data of the following things I found that the DRIVER SIDE TEMPERATURE SET POINT WAS BLANK no value, and the CABIN TEMPERATURE SENSOR, which should show the live actual air temperature in the cabin, was actually showing the Driver side Temperature setting.
So for example, it's 55 degrees and sunny OUTSIDE and i have the temperature in the cab set to 70, but it's starting to get too hot in the cab for me, like most of you guys have been having issues with. So I turn the driver side temperature to 66* F, now according to the computer the cabin temperature sensor value is now showing 66*F. So the truck thinks it is now 66* in the cabin, and it throws MORE heat at me instead of switching to cooler air to bring the temperature down to 66*. This behavior continues as i push the temperature further down until i get to LO, then it FINALLY starts throwing cool air at me. Here's some pictures to kinda help illustrate what's going on.
Here's what the truck is showing when i have the temperature set to 72*F (21*C Sorry AlfaOBD only does Celsius)
View attachment 4503
Here's what the truck is seeing when i have the heat set to HI
View attachment 4504
And Finally here's what the truck is seeing when i set the Temperature to LO:
View attachment 4505
If anybody else with a factory UAX system can log the same parameters with AlfaOBD it'd be interesting to see if the logs show the same messed up data as my truck.
I believe AlfaOBD is incorrectly interpreting the "Cabin Temperature Sensor" and "ATC Set-Point Temperature - LEFT", but I have no other reading software that will let me confirm this hypothesis.
For example, I get in the truck, it's 58 degrees out, i have the temp set at 70, so the truck thinks the cabin temperature is 70, and it knows the outside temp is 58. So the truck blows luke warm air to maintain 70, but of course you start driving the suns out, and that luke warm air quickly makes it too warm in the truck, i change the temp to 68, now the truck thinks the cabin temperature has just dropped from 70 to 68, so it starts blowing MORE heat, so i turn the temp down to 64, truck thinks the cabin temperature just went from 68 to 64, the truck thinks is getting much colder, so it blows pretty much maximum heat at me.
I force the the temperature to LO, according to the logs, the truck is now seeing 0 degrees in the cabin, however some other piece of programming sees the LO setting and overrides the climate control logic and gives me cold air. I leave it for a minute, then slowly start working the temp back up, now i set the temp back to 64, so the truck sees the in cabin temperature spike from 0 to 64, and now gives me cool air because it sees the temperature is quickly rising, and continues to give me cool air up to 68 - 70 degrees depending on the outside temperature.
@g00fy @Jimmy07 I was able to exactly reproduce the behavior g00fy reported with my factory-installed, dual-zone system.
The DRIVER SIDE TEMPERATURE SET POINT was blank, and the CABIN TEMPERATURE SENSOR was showing the Driver side Temperature setting. Who can we reach out to with this amazing observation?
This is when the temperature was set to 71 degrees.
View attachment 5034
The temperature set to HI.
View attachment 5035
The temperature set to LO.
View attachment 5036