Low Heat Output from vents.

[Laxcoach]

Hey all, hoping someone knows the trick to solve this issue.

2014, 2500, 6.7, Crew Cab, 8.4 radio. does not have individual climate controls (left / right)

Problem:
Heat from the top and bottom vents will only produce 94 on driver side and 110 on passenger side.
This is while idling with 25 degree outside temp and re-circulation is OFF.
~With re-circulation ON, temp will get up to 120 on driver side and 129 on passenger.

As soon as you drive the truck at road speed the temp goes down 20 degrees on both sides. 70ish on driver and 90ish on passenger. With the cold weather, 0-25 degrees the truck is an icebox to drive.

Work done:
~Checked temp on in/out heater core hoses. No issues found. Around 180ihs.
~Checked heater core flow, no issues found and clean water comes out.
~Checked radiator, drained and no garbage found in system.
~Checked blend door for movement. No issues found.
~Checked outside re-circulation air door. No issues found.
~Have reset the radio.
~HVAC controls seem to work, air moves from top to bottom and defrost. (but always too cold)
~AC works, no issues found.
~No codes

I feel like I am missing another fresh air intake door that would create the temperature differential between the left and right side vents. BUT remember my truck only has one temperature setting for both sides.

I also have a 2015 that has DOES have dual temperature controls and my heat is around 140 coming out of the vets at full call for heat.

Any ideas?

Freezing in Wisco.....

 

[firefighter_2000]

Mine has the dual controls and is exhibiting the same exact symptoms. Thought I had it figured out, a few months back, but it has started again. If I put the truck on high idle and increase the RPMs to about 1500 it will finally start blowing warm. I suspect that at some point the dealership put the wrong type of coolant in and now it has trouble pushing through due to plugging maybe.

 

[Laxcoach]

Mine has the dual controls and is exhibiting the same exact symptoms. Thought I had it figured out, a few months back, but it has started again. If I put the truck on high idle and increase the RPMs to about 1500 it will finally start blowing warm. I suspect that at some point the dealership put the wrong type of coolant in and now it has trouble pushing through due to plugging maybe.

~We did not see a difference at high idle, same heat output.
~We flushed the core and found no restrictions.
~The truck did have recall that involved a thermostat change and coolant top off. We feel like the problem started around that time, but the dealer is of no help.
~The T-stat opens and closes as it should and I can watch engine temp change from 190ish to 200ish and the heat output is the same.

 

[Tuesdak]

Apparently even Phoenix, AZ dealers give people this with a new RAM Cummins...

 

[Wiredawg]

Apparently even Phoenix, AZ dealers give people this with a new RAM Cummins...

View attachment 126949

Agree. When I was in MD, I made an adjustable cover for the front of radiator... mad BIG difference.

Y'all try it out and let us know if it works.

Cheers, Ron

 

[Ltngdrvr]

Issue has absolutely nothing to do with water temp or flow if the water temps checked in and out of the core are showing hot. If the core was blocked, temp on the input side would be quite a bit hotter than output side.
From the description of the symptoms it pretty much has to be a blend door issue, they may be moving when they are supposed to be but not closing all the way or the seal on one door is bad.
It may require the dash to be removed to get to the door where the issue is.

 

[Wiredawg]

I recall a post/thread here on the TDR where there is a way to recalibrate/reset the blend doors. Cant recall if it's a simple system reset pressing the two big buttons (volume and menu) on the dash, or if it was AlfaOBD action. Maybe searches will come up with the answer.

Recommend trying the dash reset.

Cheers, Ron

 

[Wiredawg]

Found it! Try this https://ricksfreeautorepairadvice.com/recalibrate-chrysler-ac-control-head/

Hope it helps. I searched "Blend Door Reset" in this forum and whole thread about 5 or 6 down.

Cheers, Ron

 

[Laxcoach]

Agree. When I was in MD, I made an adjustable cover for the front of radiator... mad BIG difference.

Y'all try it out and let us know if it works.

Cheers, Ron

Thanks, but that cover is on. We live in Wisconsin and yes, that went on first. Makes no difference.

Laxcoach

 

[Laxcoach]

Found it! Try this https://ricksfreeautorepairadvice.com/recalibrate-chrysler-ac-control-head/

Hope it helps. I searched "Blend Door Reset" in this forum and whole thread about 5 or 6 down.

Cheers, Ron

Thanks Ron, I had tried this a while back and was never sure if it worked. The directions in the post you shared a link to are better. We will try this again and report the findings.

Laxcoach

 

[Laxcoach]

Issue has absolutely nothing to do with water temp or flow if the water temps checked in and out of the core are showing hot. If the core was blocked, temp on the input side would be quite a bit hotter than output side.
From the description of the symptoms it pretty much has to be a blend door issue, they may be moving when they are supposed to be but not closing all the way or the seal on one door is bad.
It may require the dash to be removed to get to the door where the issue is.

Thanks for the advice, but I think we will dig a little deeper before ripping out the dash to look for a blend door, that may or may not be the issue, considering all servos are computer controlled. If you have a good diagram of the door in question, I would love to see that. Also, have you had this exact problem or only speculating?

Laxcoach

 

[firefighter_2000]

Found it! Try this https://ricksfreeautorepairadvice.com/recalibrate-chrysler-ac-control-head/

Hope it helps. I searched "Blend Door Reset" in this forum and whole thread about 5 or 6 down.

Cheers, Ron

There’s really not a “power” button on mine with the 8.4 screen. There’s one to turn the A/C compressor on & off... the the “OFF” button. Tried holding the recirc & each of those both, but neither worked.
Saw another one somewhere, that you held the volume & tune buttons down for 30 seconds and it would reset the system but that hasn’t worked either.
I’m thinking it’s a blend door problem somewhere also. Gag.
Craig

 

[Wiredawg]

OK, let us know what the dealer tells you.

 

[Rob5]

I would like to try this but don't know that is meant by the power button. Does anyone know what the power button is?

 

[Wiredawg]

In our 2019, power button is volume button, but gotta see my 2017 to see which one it is, I think the middle one on 4th gen 8.4 has OFF on it and turns off fan and hvac.

 

[firefighter_2000]

In our 2019, power button is volume button, but gotta see my 2017 to see which one it is, I think the middle one on 4th gen 8.4 has OFF on it and turns off fan and hvac.

The “OFF” button didn’t work. I might try the volume button just to see.

 

[Cummins12V98]

If you can read my chicken scratch there are two resets.

 

[crazy jerry]

a thermal gun on the core hoses would be first thing. after seeing them both at 180ish, it makes no sense draining the system looking for a problem that isnt there.
other places to investigate. blend door and motor. T valve if so equiped. heater controll knobs.
thermostat can easily be ruled out if engine temp is acting normal

 

[EDankievitch]

I’m having the same problem with my 2013 slt . Heat really sucks . I also back flushed the core. I had a dealer put in the wrong coolant when they did my water pump recall. I had them flush it as soon as I saw it but it was in there about a month. When I back flushed the core I got a fair amount of crud out an there was some improvement in heat output. But the heat in this truck has always sucked. I’ve tried the reset only thing I’ve found is with the system in recirculate the heat is better but as soon as you go to fresh air it cools off. Winter cover helps some but never great. I miss the heat I had in my 2012 it would blow you out of the cab. That engine also had a much hotter thermostat and single radiator. The heavy duty cooling and cooler thermostat on the 13 do not help. So I’m open to thoughts an ideas shared here. So far nothing had really helped....

 

[Wiredawg]

I’m having the same problem with my 2013 slt . Heat really sucks . I also back flushed the core. I had a dealer put in the wrong coolant when they did my water pump recall. I had them flush it as soon as I saw it but it was in there about a month. When I back flushed the core I got a fair amount of crud out an there was some improvement in heat output. But the heat in this truck has always sucked. I’ve tried the reset only thing I’ve found is with the system in recirculate the heat is better but as soon as you go to fresh air it cools off. Winter cover helps some but never great. I miss the heat I had in my 2012 it would blow you out of the cab. That engine also had a much hotter thermostat and single radiator. The heavy duty cooling and cooler thermostat on the 13 do not help. So I’m open to thoughts an ideas shared here. So far nothing had really helped....

ED,

It's possible it is what it is. If you are seeing the same heating performance on your truck since new, then it's possible it's as good as it gets. Sounds like you already have the RECIR option working.

On ALL the vehicles I've ever owned, I've placed the heat in RECIR to get better heat and same with A/C in the Summer. I seldom run mine in fresh as I get other vehicle fumes and other smells in the cab. On my 19 1500 gasser and 17 5500, I cheat and turn on heated seats and steering for about 10 minutes, then gets too hot. I like both of mine, and the 5500 did great in Northwest a back in 2018 when camping there.

So, not much help offered, just what I do with my trucks.

Cheers, Ron