Weird HVAC issues

[nlambert182]

This is gonna be long, so bear with me. It has me baffled.

Last winter my heat only worked on the passenger side, so I flushed the core and restored heat to the truck. It lasted for a few weeks before tapering back off.

Fast forward to June and my AC stops blowing cold, so I take it into the shop. They noticed that it was slightly low on freon but not enough to stop it from working, but they recharged it and added dye. Never could find a single leak anywhere and the AC started blowing ice cold again. Since they didn't find a leak and it was working, I forgot about it.

HOWEVER.... I started noticing that the coolant fan runs a LOT more than it used to while my coolant temps never break 200 degrees. Any outside temp over 90 degrees and my fan runs pretty much non-stop. On my 24 mile commute home in 85 degree heat, the cooling fan will finally shut off about 10 minutes before I get home. My coolant temps on a 95 degree day stay around 192 F.

This past week I noticed that it was taking the truck a lot longer for the AC to cool it back down and I noticed that I could feel the cold air surge in the vents. It would be cool for a bit, and then get a blast of cold air before going back to relatively cool air. This cycle seems to repeat itself every 20-30 seconds. The fan speed doesn't seem to surge, but the temperature does. The fan speed will stay wherever I set it.

To eliminate one possible culprit, I disabled auto climate control and manually set the temp and fan speed. No change. I do still get cold air (eventually) and once it cools down it gets pretty chilly in there.

This issue made me remember my heat situation, so I also checked heat again and have no heat coming from any of the vents. I can switch between all of the vents with no issues so I'm not convinced that it's a blend door issue (but it's possible). Heater core doesn't appear to be clogged.

Anyone seen this before? Could it be an HVAC control module? Are there other tests I can perform? I would try the recalibration, but not sure how that works on a dual zone. I never could get it to do it.

There are zero active or stored codes in any of the modules. I'm trying to figure this out before winter hits again, and if I can avoid paying a shop a ton of money to diagnose it I'd prefer it. But... if that's what it takes, that's what it takes.

 

[Schimcha]

Did you ever get this figured out? It sound pretty similar to some of the issues I’ve been having.

 

[markabby]

Did you ever get this figured out? It sound pretty similar to some of the issues I’ve been having.

i guess we'll have to wait a few more months

 

[Schimcha]

i guess we'll have to wait a few more months

 

[nlambert182]

Yep. It was a clogged heater core and evaporator core. Got it out of the shop on Friday. Works perfectly fine now.

 

[WillyBo55]

I had a similar problem with my 2014 ram 1500 last winter. A small amount of heat coming from the passenger side vents and zero heat coming from the drivers. I flushed entire cooling system with no luck and ended up replacing my blower motor and actuator that are both located behind the glove box. Neither fixed my no heat issue. Summer came so I didn’t need heat anymore and I didn’t have the tools to calibrate the new actuator I installed so I removed the actuator for the summer because the door rests in the cold position.A few months ago I replaced my heater core and had the whole dash out and a lot of things unplugged of course. I re installed the actuator upon completion of the heater core replacement. Original Heater core was clogged and the replacement fixed my heating issue. My Heat and cold settings work fine. But if my truck has been sitting for any length of time it starts out blowing on the floor. No matter what selection I choose it won’t change from the floor. After I’ve turned my truck off and on a few times. It will start blowing from the selected position. I now have Mx+ and Alfaobd so I am capable of calibrating actuators . I can’t seem to find any instructions on how to properly calibrate actuators. Not even sure which actuator controls which vents the air comes out of to even attempt the calibration.

Sorry for the lengthy post. Any and all help would be appreciated.

 

[GTyankee]

The 2013 or 2014 & everything newer with the HVAC System is self calibrating.

I think what you do is push the left HVAC control button for the slow count of 10
then release that button
then push it again until the little light on that button lights up & let it do its thing

You can search the many YouTube videos to find it, that is where i watched it

2010 Dodge Ram No Heat? How To Calibrate The A/C Heat Blend Door Temp Actuator Location

#car #dodge #howto #automotive #diy #youtube #cars #new #subscribe #like #fyp #mopar #shorts 2010 Dodge Ram No Heat? How To Calibrate The A/C Heat Door Blend...

www.youtube.com

 

[nlambert182]

I had a similar problem with my 2014 ram 1500 last winter. A small amount of heat coming from the passenger side vents and zero heat coming from the drivers. I flushed entire cooling system with no luck and ended up replacing my blower motor and actuator that are both located behind the glove box. Neither fixed my no heat issue. Summer came so I didn’t need heat anymore and I didn’t have the tools to calibrate the new actuator I installed so I removed the actuator for the summer because the door rests in the cold position.A few months ago I replaced my heater core and had the whole dash out and a lot of things unplugged of course. I re installed the actuator upon completion of the heater core replacement. Original Heater core was clogged and the replacement fixed my heating issue. My Heat and cold settings work fine. But if my truck has been sitting for any length of time it starts out blowing on the floor. No matter what selection I choose it won’t change from the floor. After I’ve turned my truck off and on a few times. It will start blowing from the selected position. I now have Mx+ and Alfaobd so I am capable of calibrating actuators . I can’t seem to find any instructions on how to properly calibrate actuators. Not even sure which actuator controls which vents the air comes out of to even attempt the calibration.

Sorry for the lengthy post. Any and all help would be appreciated.

I dunno if your actuators need calibrating. Just discussing this in another thread and something I completely forgot about, but the truck is automatically going to start with air blowing from the dash/floor vents and will switch itself when it determines that it is no longer required. All 4 of my Rams have always done this. Are you saying that yours will never switch over on it's own?

In the winter, it's to help defrost the windshield. In the summer, I presume it's to try and circulate the air as quickly as possible to help cool it down. Eventually (and I don't know the criteria it uses to decide when) the vents will switch to whatever I have them set at.

For calibration, I haven't found a way to do it with the dual zone system/8.4 UConnect. It doesn't work using the steps GTYankee mentioned above. I have seen it work with the single zone though.

 

[WillyBo55]

I had tried to calibrate at the beginning through Alfaobd but not really knowing what I was doing. At one time I had the air full blast and you could hear the blower going but air wasn’t coming out of any vents. I tried the reset demonstrated in the video above with my truck in the run position but it didn’t seem like the light on my recirculation button blinked in the same sequence as on the video and nothing changed. I let the truck sit over night and tried it the next day and still nothing but floor vents blowing. I tried the reset with the engine running and killed the engine. I tried it the following day and the air was blowing out the front vents which was the selected mode. It worked normal for two days. On my trip home yesterday (a little over two and half hour drive) it blew on the the floor the entire way no matter the mode I selected. I pulled over twice and turned my truck off each time thinking I might come back out and it turn on and it be right but had no luck. I can hear a clicking sound coming from the glove box. Sounds like a pair of plumbee crimping pliers being used. Like small gears being clicked if that makes sense. Also had a errand to run after my long trip home and my mode selection worked as it should front vents defrost or floor

 

[WillyBo55]

24 hours later and everything is working as it should like it was yesterday after my trip. Also the actuator I installed was not a mopar part. And was specified on rockauto that it would need calibrating. Don’t know if just the oem actuators or self Calibrating or what

 

[GTyankee]

Mopar Actuators are stronger, as in beefier
They also work with the Hvac control module to self calibrate

The Clicking noise that you hear over at the glove compartments, is likely broken teeth on Blend Door Actuator..

I will look up a video that should help you

⫷ Ram Dash Clicking or Knocking? Blows air but wont get cold or hot? Won't blow in face? ⫸

Ram Truck dash clicking or knocking? This video might help you figure out what needs to be replaced or might give you a starting point to find your issue. â¬â¬...

www.youtube.com

this video is a DUAL ZONE HVAC System
most of the actuators locations are the same

Ram 3500 Ep.2: How to Fix Blend Door Actuators

Now that we've replaced this 2012 Ram 3500's blower motor, it sure blows! Trouble is, you can't direct it WHERE to blow...and proper heat is very important u...

www.youtube.com

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hopefully, you noticed that when he manually worked the White Plastic pieces, you heard a thump.
That was the Door that is inside of the HVAC box & that means that the door is still attached
That is what you want to hear & feel