Join Date: May 2013
Location: Woodstock, IL
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Standard in 19 with CTD option
Jimmy07, thanks for the diagram.
The 2019's (haven't checked the 20's) has an auxiliary supplemental cabin heater as standard with the Cummins engine option, regardless of trim.
I have been testing it to see the effectiveness. Here is what I have observed. On a cold morning, below 35F, within about 2 minutes after start, when I place my hand over the windscreen defrost vent, I can feel very warm air. Everywhere else blows a small amount of cold air. After another minute I can feel warm/hot air out of the side window defrost vents. The floor vents and face vents now blow cool air. When the engine temps get to about 125F, hot air is available at all vents, and the entire cab is already warm. This is on my Laramie trim model, Auto climate on and set to 74F drivers, 73F pass. I had the same results last week when temps at startup were single digits.
So it seems like the heater kicks in to the windshield defrost vents first, then transitions to the side defrosters, until the engine can start to step up give heat around the 125F mark.
On a side note, my 2007 Mercedes ML diesel has the same heater set up, but the heater pushes hot air to EVERY vent and has the smaller cabin completely warm by the time I get to my first subdivision stop sign. The Ecodiesel Jeeps and RAM 1500 has also had this feature for years.
2019 RAM 2500 Laramie CTD, Crew Cab, 4X4 all options except rear air susp, Black Forest Green Pearl.