HVAC Issues - in-depth testing done

[Hilderman85]

Hey all, I have a 2013 ram 1500 Laramie, and I can't figure out what the issue is with my HVAC system. It has the 8.4 uconnect system and dual climate controls.

What's happening:
erratic actuator response - right now I can get face and defrost ventilation, not floor ventilation. Prior to removing the battery cables all I could get was floor ventilation.
Blend door actuator response is also intermittent.

I have changed the HVAC control module and saw no change in the system.

I have alphaOBD, first I ran a calibration on the system:
Initially I was getting these responses.
Actuator 0 (floor door) - passed
Actuator 1 (defrost panel door) - failed
Actuator 2 (right temp) - passed
Actuator 3 (recirc) - passed
Actuator 4 (left temp) - failed

After battery disconnect for an hour.
Actuator 0 (floor door) - failed
Actuator 1 (defrost panel door) - failed
Actuator 2 (right temp) - passed
Actuator 3 (recirc) - failed
Actuator 4 (left temp) - passed

today I got this after changing the HVAC module and doing a battery disconnect for 2 hours.
Actuator 0 (floor door) - Failed
Actuator 1 (defrost panel door) - passed
Actuator 2 (right temp) - passed
Actuator 3 (recirc) - failed
Actuator 4 (left temp) - failed

When I run diagnostics, there is no signal being sent to the actuators that are failing.

I took the truck for a ride today now that the defrost was working (I'm up in Canada and its cold.. need defrost to see. And the windows all fogged up like crazy except for the passenger side windshield). It doesn't smell like anti-freeze, and up until a week ago things were working perfectly.

My question is, what can be causing this erratic behavior other than the HVAC (AC / heater) control module?

Thanks for any help

 

[Hilderman85]

Hey all, I have a 2013 ram 1500 Laramie, and I can't figure out what the issue is with my HVAC system. It has the 8.4 uconnect system and dual climate controls.

What's happening:
erratic actuator response - right now I can get face and defrost ventilation, not floor ventilation. Prior to removing the battery cables all I could get was floor ventilation.
Blend door actuator response is also intermittent.

I have changed the HVAC control module and saw no change in the system.

I have alphaOBD, first I ran a calibration on the system:
Initially I was getting these responses.
Actuator 0 (floor door) - passed
Actuator 1 (defrost panel door) - failed
Actuator 2 (right temp) - passed
Actuator 3 (recirc) - passed
Actuator 4 (left temp) - failed

After battery disconnect for an hour.
Actuator 0 (floor door) - failed
Actuator 1 (defrost panel door) - failed
Actuator 2 (right temp) - passed
Actuator 3 (recirc) - failed
Actuator 4 (left temp) - passed

today I got this after changing the HVAC module and doing a battery disconnect for 2 hours.
Actuator 0 (floor door) - Failed
Actuator 1 (defrost panel door) - passed
Actuator 2 (right temp) - passed
Actuator 3 (recirc) - failed
Actuator 4 (left temp) - failed

When I run diagnostics, there is no signal being sent to the actuators that are failing.

I took the truck for a ride today now that the defrost was working (I'm up in Canada and its cold.. need defrost to see. And the windows all fogged up like crazy except for the passenger side windshield). It doesn't smell like anti-freeze, and up until a week ago things were working perfectly.

My question is, what can be causing this erratic behavior other than the HVAC (AC / heater) control module?

Thanks for any help

Also, I have held the temp buttons and done a full "reset" of the system and that did nothing, I also held the volume and tune button to turn the system off and on to no avail as well.

 

[GTyankee]

It does not take much to physically watch 4 of the Actuators move the arms that move the doors
Of course you can hear the fan speed up, etc

3 screws allows you to remove the Radio Fascia
Glove boxes are almost as easy

 

[Hilderman85]

It does not take much to physically watch 4 of the Actuators move the arms that move the doors
Of course you can hear the fan speed up, etc

3 screws allows you to remove the Radio Fascia
Glove boxes are almost as easy

I replaced the floor actuator (behind glove box), after turning the truck on it actually calibrated and I felt it turning. After calibration it does not respond to the soft controls on the screen.

I tested the one I took out of the truck and it is operating correctly.

 

[Hilderman85]

I got a reply to a previous thread on here, that member replied:

Hey Darleyhavidson,
Having a similar issue to what you had, to clarify, are you saying that a single BDA failing can throw off the entire HVAC system?

Yes, basically. I can't substantiate the "how". But the failed BDA at firewall, once replaced, caused the 8.4 screen HVAC controls to work/respond correctly. I did everything else to try and fix the original issue, this was the last ditch effort. Been working correctly for the last 30,000 miles.

-----------------------------------------------------------------------------------------------------

So perhaps if I change out all of the actuators (one of them is intermittent, or completely failed) that will resolve the issue.

 

[Jeepwalker]

This is an obvious suggestion, but how is your battery and have you cleaned the grounds really well and grounds to the frame and body? All the electrical signals go through the grounds so any problems there can potentially 'goof up' electronics. On modern vehicles there are wires to ground all through-out the vehicle (multiples to the floor pan, behind panels, rear of body, etc). But if the battery to body is corroded I would look into that if you haven't. Because what you're describing sounds like whacky control logic which can be caused by improper voltage & grounding.

Is your truck in a warm area? This is going to sound crazy, but I've had a couple times where I needed to remove a module, bring it indoors overnight, and tie the battery cables together (to drain TIPM). But if your truck is already indoors, than you can skip this idea. But when I've brought the module into the warm overnight and installed it the next day (as suggested by others on a non ram forum) ...it worked. And maybe it was because the module power having been disconnected, drained fully too.

 

[Hilderman85]

valid question as I did not state this earlier, the truck is parked in a warm garage every night, and the battery terminals are completely clean, the whole truck has been meticulously maintained and I haven't seen any signs of faulty/damaged/corroded wiring.

I have connected the pos/neg wires to drain the TIPM in my previous diagnosis as well.

I called a local shop, one that did the BDA on a friends truck 2 years ago. He said after doing multiple fixes of this issue, he has found the firewall BDA is most common to have failed, and it causes similar issues to this (erratic and failing components throughout the HVAC system). I could rip it all apart, and check/replace everything and feel my way through it. but I think in this rare occasion, I will just let the shop do it as they have done it many times before.

I appreciate all the help and comments, I will update when I get the truck back to see what the issue actually was. it goes in monday, so I'd guess a week or so from now I should have some sort of response.

 

[Hilderman85]

UPDATE - After 2 different shops looked at the truck (second had a dealer scanner) , they couldn't find anything actually wrong with the truck. It had error codes for floor defrost actuator, recirc door and left temp blend door, but all were functioning when the actuators were tested.
In the end the service manager told me they "Re-clocked" the actuators... I asked him what that means as the actuators spin counter clockwise with pos/neg power and counter clockwise with neg/pos power.. They simply said the actuators have a set rest position (as if it need to be in the 12 o'clock position when installed).

then I talked with the mechanic that did the work, and he said "I dunno man, I took the 3 actuators that were accessible out of the truck, tested them to make sure they were spinning and put them back in, and it just started working"

So, I personally think there was a bad connection in one of the harnesses, and after unplugging and replugging it in a bunch of times it is working properly again.

pretty stupid way to spend a grand, but it's all working just fine now with no new parts installed. all original back in the vehicle.

So if anyone needs a new HVAC control module for a 2013 ram, I've got one. and it was checked and verified that it has the most up to date software.

 

[Jeepwalker]

Great. Glad it's working. Long post here but I hope the info helps:

If you plan to hang onto your tk, you might also want to hang onto the controller a while longer too. They've been known to fail. Or throw it on ebay. I surmise most of the time the HVAC controllers don't really fail, it's other things in the system that get resolved in the de-bugging process ...along with the controller swap-out. Maybe it was a bad ground, or the connections were flaky. They say (and GM did a test to discover this ...back in the early 90's), only a small percentage of returned ECMs are truly failed.

Generally speaking most automatic systems do frequent recalibrations, so the motors know where they are. On some vehicles it might be every x number of starts. Sometimes it's upon shut-off. It drives the motors full open, then full closed. There's usually a secret combination of 'key pushes' on the HVAC controller an owner/tech can do to force it to recalibrate. Of course a good scanner can do it too.

On our older Grand Cherokee, it looks for a baseline a lot. There's a broken outside air door and because it can't find the closed position (because the door has broken off of it's shaft) it continues to 'hunt' for 'closed'. After so many tries, it gives up. It's pretty easy to hear if ya listen carefully. It'll do it well after the vehicle has been shut off too.

 

[Jeepwalker]

There could also be a weak electrolytic capacitor or bad solder joint in the controller too. That's real common as electronics age. If you were the handy type you could pop out the controller, and check the capacitors with an ESR Meter (check ebay) ...like I had to do with a dishwasher yesterday. They're one of the highest failing items in electronics, generally due to: age, continued exposure to interior cabin heat in the summers, actual leakage of the electrolytic gel inside.

Solder joints that have low integrity, can work for years, but are a weak link in an electronic system. Then they can become intermittent (often good when cold, bad when hot). Their demise is often exaserbated by years of extreme temp swings that you see in your area. You combine these two and suddenly that amounts to like 80% or more of failures.

It might be that your failure IS the controller but in the very cold temps (now), there was some 'shrinkage' of solder joints enough that it works now ... ...but you'll have to see when it warms back up. You can usually visually see weak solder joints, and capacitors can be tested in-circuit with even a cheap ESR meter (should be a mechanics go-to tool). And solder joints can be touched up with a solder iron in no time. Replacement capacitors can be bought off ebay. Lot of good ebay videos on this topic.

Electronics and microprocessors need predictable 'smooth' conditioned power. When it's not (weak points outlined above), their logic and decision-making gets 'off' ..sort of like when a person gets drunk. Soooo if you have continued issues, I wouldn't discount those two items. (of course after you've make sure your tk grounds are absolutely good)

 

[Livinalittle]

Big bump, I apologize.

My truck just started having this exact issue.
2013 Sport with 8.4 Uconnect and dual climate control.

I started with the inexpensive option and replaced the three BDA’s that are easy to access as well as clean up the ground wires on the battery and PDC. No luck unfortunately.

I used my OBDLink+ to do an actuator test, they all failed despite being new which is pointing me to the computer.

My next step is the AC and Heater Module, if that doesn’t work I think I’ll be pulling the dash and replacing the BDA at the firewall.

If anyone else has experienced this issue I’d love to hear what your solution was. Thanks in advance and I’ll post an update when the module arrives in Jan.

 

[shiett0429]

Big bump, I apologize.

My truck just started having this exact issue.
2013 Sport with 8.4 Uconnect and dual climate control.

I started with the inexpensive option and replaced the three BDA’s that are easy to access as well as clean up the ground wires on the battery and PDC. No luck unfortunately.

I used my OBDLink+ to do an actuator test, they all failed despite being new which is pointing me to the computer.

My next step is the AC and Heater Module, if that doesn’t work I think I’ll be pulling the dash and replacing the BDA at the firewall.

If anyone else has experienced this issue I’d love to hear what your solution was. Thanks in advance and I’ll post an update when the module arrives in Jan.

Any update on this?

I've tried what I feel like is everything listed above EXCEPT the firewall BDA, and I'm thinking that is my issue.

I will be pulling the dash & HVAC this weekend & replacing all actuators (with new OEM), all doors (from blend door USA), along with the heater core and evap since everything is already out.

I'll post an update once I have (hopefully positive) results, but would love to know if this worked for you.

 

[GTyankee]

The OEM Actuators are actually stronger than the after market actuators, ( DORMAN brand ), & only the OEM works with the vehicles Calibration setup.

Sometimes the OEM Actuators Gears have a tooth break off,
I have seen YouTube videos where the Gear can be rotated to a position where that broken tooth is not used.
You can open up the actuators & they will work when opened up, just have the gears facing upwards.

some videos that could be handy

2009 Dodge RAM 1500 Blend Door repair

Two options to fix the clicking blend doors on your Dodge Pickup. One option allows you to fix the issue at no charge. The other option shows one actuator ...

www.youtube.com

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

Gen 4 2013 Dodge Ram heat on passenger side, cool or warm on driver side.

Gen 4 2013 Dodge Ram heat on passenger side, cool or warm on driver side.I flush the heater core to fix the heat, no heat problem.Follow up video:https://you...

www.youtube.com

One thing that almost all the YouTubers get wrong, is the proper terminology for the Actuator Positions

What i will refer to as the first actuator is:

with the upper glove box out, to the upper right, there is the
Recirculation Door & Actuator

with the lower glove box out, near the lower left corner of the glove box door, you will find the Blend Door Actuator, the Blend Door itself is within the unit, it changes the Flow of Air, from either Through the Heater, or to bypass the Heater.

If you were to remove the dash panel that surrounds the RADIO,
you would see 2 more Actuators
These actuators Operate Mode Door 1 & Mode Door 2
they control where the Air travels, Defrost, Floor, dash vents

 

[Ken226]

The OEM Actuators are actually stronger than the after market actuators, ( DORMAN brand ), & only the OEM works with the vehicles Calibration setup.

Sometimes the OEM Actuators Gears have a tooth break off,
I have seen YouTube videos where the Gear can be rotated to a position where that broken tooth is not used.
You can open up the actuators & they will work when opened up, just have the gears facing upwards.

some videos that could be handy

2009 Dodge RAM 1500 Blend Door repair

Two options to fix the clicking blend doors on your Dodge Pickup. One option allows you to fix the issue at no charge. The other option shows one actuator ...

www.youtube.com

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

Gen 4 2013 Dodge Ram heat on passenger side, cool or warm on driver side.

Gen 4 2013 Dodge Ram heat on passenger side, cool or warm on driver side.I flush the heater core to fix the heat, no heat problem.Follow up video:https://you...

www.youtube.com

One thing that almost all the YouTubers get wrong, is the proper terminology for the Actuator Positions

What i will refer to as the first actuator is:

with the upper glove box out, to the upper right, there is the
Recirculation Door & Actuator

with the lower glove box out, near the lower left corner of the glove box door, you will find the Blend Door Actuator, the Blend Door itself is within the unit, it changes the Flow of Air, from either Through the Heater, or to bypass the Heater.

If you were to remove the dash panel that surrounds the RADIO,
you would see 2 more Actuators
These actuators Operate Mode Door 1 & Mode Door 2
they control where the Air travels, Defrost, Floor, dash vents

Isn't there one way back, on the firewall side of the HVAC box?

 

[GTyankee]

From what i think that i remember:

The Mega Cab & Vans have 2 BLEND doors & therefore 2 actuators for the Blend Doors

I still do not know for sure about the Single & Dual ZONE HVAC systems

Unless that means, that there are separate TEMPERATURE controls for the Driver & Passenger

similar to this unit

 

[kaldridge]

The OEM Actuators are actually stronger than the after market actuators, ( DORMAN brand ), & only the OEM works with the vehicles Calibration setup.

Can you explain how this black magic works? I've been fighting with my blend doors all winter and I'm curious why a pos/neg neg/pos directional motor of any make wouldn't work with the calibration setup. Also I really really really don't want to drop 250 bucks for new blend door actuators.

 

[shiett0429]

Well, I can confirm that replacing the blend door between the firewall and HVAC box has fixed my issue. Quite the job, but I was able to have everything pulled apart and put back together in a day. I wound up also throwing a heater core, evaporator, and upgraded blend doors at it while everything was apart.

I made sure to use all new OEM actuators (the part has actually been superceded by a newer version, which I would assume is better?), and once put back together, it passed all calibrations first try.

 

[GTyankee]

I would also do what you did, IF my HVAC System had to be removed from the vehicle

I would spend the extra $$$
for these parts
HVAC Heater Core
HVAC Condenser
4 or in some cases 5 OEM Actuators
4 or more HVAC Doors, in my case, i would spend the extra $$$ & buy the Door Kit, made by

Blend Door USA

We manufacture solid aluminum blend doors. The heater doors are CNC machined from solid aluminum and are guaranteed for life. Our blend doors fit the OEM actuator for a do it yourself install. The perfect fix for Dodge Ram trucks and Jeeps. Our kits are the best durable heater box repair on the...

www.blenddoorusa.com

....................................................................

I still don't know, if the HVAC Units that have the
5 Actuators
are just in the VANS & MEGA Cabs
OR
do the DUAL Zone HVAC Systems also have the 5th Actuator, that is located between the Fire Wall & the HVAC Box

( or am i missing something else ? )

 

[kaldridge]

I would also do what you did, IF my HVAC System had to be removed from the vehicle

I would spend the extra $$$
for these parts
HVAC Heater Core
HVAC Condenser
4 or in some cases 5 OEM Actuators
4 or more HVAC Doors, in my case, i would spend the extra $$$ & buy the Door Kit, made by

Blend Door USA

We manufacture solid aluminum blend doors. The heater doors are CNC machined from solid aluminum and are guaranteed for life. Our blend doors fit the OEM actuator for a do it yourself install. The perfect fix for Dodge Ram trucks and Jeeps. Our kits are the best durable heater box repair on the...

www.blenddoorusa.com

....................................................................

I still don't know, if the HVAC Units that have the
5 Actuators
are just in the VANS & MEGA Cabs
OR
do the DUAL Zone HVAC Systems also have the 5th Actuator, that is located between the Fire Wall & the HVAC Box

( or am i missing something else ? )

My '16 3500 has dual zone driver and passenger and has 5 actuators.

 

[shiett0429]

I would also do what you did, IF my HVAC System had to be removed from the vehicle

I would spend the extra $$$
for these parts
HVAC Heater Core
HVAC Condenser
4 or in some cases 5 OEM Actuators
4 or more HVAC Doors, in my case, i would spend the extra $$$ & buy the Door Kit, made by

Blend Door USA

We manufacture solid aluminum blend doors. The heater doors are CNC machined from solid aluminum and are guaranteed for life. Our blend doors fit the OEM actuator for a do it yourself install. The perfect fix for Dodge Ram trucks and Jeeps. Our kits are the best durable heater box repair on the...

www.blenddoorusa.com

....................................................................

I still don't know, if the HVAC Units that have the
5 Actuators
are just in the VANS & MEGA Cabs
OR
do the DUAL Zone HVAC Systems also have the 5th Actuator, that is located between the Fire Wall & the HVAC Box

( or am i missing something else ? )

Yup, that's exactly what I did. Though looking back, I probably could have reused my evap & heater core. They showed little to no contamination on the fins, or signs of leaks. I should mention that this was on my 2018 Ram 2500 SLT (6.7L) with the newer 8.4 uconnect head unit, which thankfully, came with a cabin filter from the factory. I should add that I only have 90k on the dash as well (add this to the list of problems I've had all before 100k)

As for the 4 or 5 actuators, mine had 5. I believe it is the dual zone that adds the 5th door for the passenger blend door. I also believe that the 5 BDA trucks are the only ones that have the BDA in between the firewall and the HVAC box. Don't quote me on that though.

The installation of the blend doors from blend door usa was a breeze, and the step by step video is what made this whole process doable for me. Again, my blend doors were not broken and didn't even look fatigued, but I installed the upgraded ones just for peace of mind.

I will say, if you make sure you have all the parts needed to complete the job, then it's really not a bad 1 (maybe 2 if your garage is on toddler duty like mine) day job.

The evap and expansion valve both came with new o-rings for between the valve and the evaporator, but I did forget to pick up the seal that goes between the expansion valve and the lines. They looked pretty cruddy, so I had to run to the dealer to grab some new ones.