# Air-conditioning problem. Cooling one side only 2004 Phaeton V8



## johnmo (Jul 28, 2013)

Had a few warm days last week and noticed a lack of cooling from the HVAC system.
Local temps cooled off a bit but I decided to see what I could find out before I got hot again.
Started playing with the system in the driveway and discovered good cooling capacity on the passenger side but just mildly cool air coming out of the drivers side vents. This seemed to be true on both the front and back. I hooked by laptop up and noticed single digit temps at the evaporator. When I brought the temps down on the climate control the right side exchanger would get down to around 12C but the Left would struggle to get to 22C and if I moved the passenger side requested temp up the drivers side exchanger temp would follow even though the requested temp on the drivers side was low. There was a display for the Left and Right regulating valves but they seemed parked at 0.0 unless I made a cabin temp change.
I am guessing the left regulating valve is the problem but know nothing of how this system works.
Could find no other thread relating to this problem but maybe there is one out there that I missed.
Any insight would be great.
John


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## jyoung8607 (Feb 14, 2006)

It does seem possible you have a stuck-open heater valve. Try setting the system to ECON, which disables the AC compressor, and set the temperature control as low as it will go. In that configuration, the fan should be running at fairly high speed and temperatures throughout the system should settle out at ambient. If your post-heater core temperature on one or both sides still wants to drift above ambient, you'll know what's wrong.

References you might be interested in:

* VW Self Study Program 271, which describes the Phaeton climate control system in great detail.

* As a supplement to the SSP, a logical air flow diagram I put together while working on Phaeton Climatronic support for VCDS.

Jason


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## PanEuropean (Nov 3, 2001)

johnmo said:


> ...I am guessing the left regulating valve is the problem but know nothing of how this system works.


Hi John:

I think your guess is probably quite accurate. The Phaeton HVAC system has a heck of a lot of damper doors and flap motors inside it - about 30 different actuators. It is not uncommon for one of these actuator motors to fail. Some are easy to get at, others are absolute murder to get at and require an extraordinary amount of disassembly.

Do you have a diagnostic scan tool (VCDS, or VAG-COM), or could you perhaps get someone with a VCDS in your town to run a diagnostic scan and give you the results as a text file? The HVAC system does an excellent job of self-diagnosing and will generate a fault code if a component is not working. From the specific fault code, you can determine exactly which component is causing the problem.

If you don't have a diagnostic scan tool yourself, have a look at the first topic that is stuck to the top of the forum topic list in the VAG-COM Diagnostic Forum here on Vortex. You can type in your Zip code and find a list of VW enthusiasts in your area who are willing to help you out by carrying out a diagnostic scan. The process for doing the scan is identical to all VW products, the person doing the scan doesn't need to have even seen a Phaeton before.

Get the scan done, then post the details of the fault code and we'll be able to let you know how easy or difficult to fix your problem is.

Michael


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## johnmo (Jul 28, 2013)

I have a VCDS but have not had a need to use it much.
The only fault code on the Climate control module was a Low refrigerant fault. 
I cleared the fault and it did not come back
While the freon is most likely low, I don't think that is the problem because it seems to cool fine on one side and when I monitor the evaporator temp it gets down in the single digits.
I was also monitoring something labeled like left exchanger and right exchanger. Here is where the problem seem to kick in because the right side temp gets dow to around 12C but the left never below 24C which is consistent with what i am feeling in the cabin.
How is the heat transferred to the cabin? Is air blown over the evaporator and into the cabin, or is there some other secondary heat exchanger?
Is there something I am missing with the VCDS?
I will hook it up again tomorrow and take better notes.
John


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## PanEuropean (Nov 3, 2001)

Hi John:

Air passes over both a heater core and an evaporator before it is directed to the various outlets that serve the left and right side of the car.

If you are getting cold air (12°C) out of one side of the car, then that rules out any possible problems with the AC system, as you have observed.

If the other side of the car won't blow air of the same temperature when set to the same set-point, that suggests that one of the damper doors is not operating properly. If you are not getting a fault code for a damper door, then perhaps you just need to carry out the "basic settings" for the HVAC controller. That task cycles the various damper doors through full range of motion and the car then learns what the 'fully open' and 'fully closed' positions are for each flap. You can accomplish this by going to the "basic settings" menu of VCDS, controller 08 (the AC controller).

Prior to doing this, press the CLIMATE button below the screen, then press the RESET button, then refer to the soft-keys on the screen and choose the 'reset climate settings' (as opposed to 'reset all') and press the appropriate key beside 'reset climate settings'.

Michael


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## vinyin (Feb 28, 2010)

I had the same thing. The passenger side got nice cold but the drivers side just blowed uncooled warm air (front and rear). 
This mostly occurred when the car was sitting in the sun. 
The only error was "loss of refrigerant". 
After refilling refrigerant (I did that myself - r134a) the drivers side is now cool too. 

Maybe the vaporizer doesn't get cool all the way on both sides when there is not enough gas in the system. 

,Michael


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## johnmo (Jul 28, 2013)

Thanks for the advice the diagrams were very informative. 
With the system in ECON, the temps are consistent left to right just slightly elevated from the ambient air temp. I tried to cycle the left regulator valve by going to LOW temp and then to HIGH and then back to LOW. It performed the function but it did not seem to have any effect on the AC problem. 
Could not see how to calibrate damper servos. Is the Climate button on the Car or the VCDS? Is the Reset a soft key or a hard key?
I think tomorrow I will try to reset the dampers again and them maybe check the charge on the refrigeration system.
Need to study the Climatronic training documents.
Thanks,
John


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## Bindaham (Apr 4, 2014)

I had the same issue an hour ago, the driver side blows warm while passenger side was nice and cool. I turned off the middle vent for a minute and turned it on again and cold air came back on.

My recent scan had these HVAC faults:

Address 08: Auto HVAC Labels: 3D0-907-040.lbl
Part No: 3D0 907 040 G
Component: Climatronic D1 1132 
Coding: 0000001
Shop #: WSC 00000 000 00000
VCID: 224BE670FE0C4C0EAD3-5140

3 Faults Found:
00711 - Left Footwell Flap Positioning Motor (V108) 
005 - No or Incorrect Basic Setting / Adaptation
00229 - Refrigerant Pressure 
001 - Upper Limit Exceeded - Intermittent
00445 - Loss of Refrigerant 
000 - -

I erased them and scanned again, only 00711 persisted. 

Prior to that scan, all vents blew warm air. 

Strangely enough, in both instances that I had all vents blow warm happened after I had turned on the solar circulation function when parked with no shade! 

Regards,

Salah


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## PanEuropean (Nov 3, 2001)

Very interesting what we have learned from the various posts in this discussion.

It appears that if the refrigerant pressure is low (meaning, there is a lack of refrigerant in the system, not a total loss, but less than there should be), the car does not cool bilaterally - only one side gets cool air.

I think Michael (Vinyin) put his finger on it when he suggested that evaporation of the refrigerant is not happening all the way across the evaporator surface when the system is low on refrigerant.

Fascinating.

Michael


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## Bindaham (Apr 4, 2014)

Michael,

Happy to report that the A/C is working well with no issues in the past few days with no mechanical nor programming intervention since last time done.

Regards,

Salah


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## Bindaham (Apr 4, 2014)

One side cooling only came back, in the wrong time when it's getting warmer around here. Latest scan showed loss of refrigerant.


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## Bindaham (Apr 4, 2014)

Update:

Apparently my A/C leak was from the upper filling valve which was not tightly screwed from the inside. All is well with a fresh load of refrigerant.


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## Paximus (Aug 26, 2011)

Hi Salah,

Thanks for reporting the end result. It looks like the problems caused by low refrigerant can be quite subtle, rather that simply low cooling.

Cheers,
Chris


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## [email protected] (Jul 1, 2015)

*Air-conditioning problem. Cooling one side only 2004 Phaeton V8*

Hi,

I have VW Touareg 2004 and has cooling problem. Driver side vent works well and is cooling though cooling low looks bit low.. The passenger side vent is not cooling, though blower is on. From mail thread i understand this could be due to low refrigerant. Does it mean i get the gas filled in compressor and cooing should work on passenger side vent also. Please advice. Any suggestions appreciated. Regards Surinder


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## Paximus (Aug 26, 2011)

Hi Surinder,

Welcome. Although the info here relates to the Phaeton, your Touareg probably has a similar control system. If it does, then it will be well worth having your air conditioning system re-gassed. This has fixed the 'one side only cooling' problem in a number of Phaeton cars.

Your a/c technician can also check for a leak, but since the small molecules of the refrigerant pass through various membranes and escape under normal conditions, it's possible that you will not find one.

If that does not help, please continue to read the threads about reading the controller diagnostics and faults in flap motors.

Regards,
Chris


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## sachverhalte (Sep 16, 2007)

*Climate system air flow issues*

Hi All,

I'm having intermittent air flow issues on all functions. The defrost function doesn't work at all. The VAG shows errors on several flap controllers. The first step was to replace the driver's side battery with a new OEM model. It didn't seem to help. I'm hoping one of the more knowledgeable forum members can help. On 005 fault codes seems to indicate a need for part replacement. Does the 014 fault code just call for a new adaptation routine?

My plan is to address the v71 and v113 issues and see how much of my problem it solves. Fixing all of these may be expensive and not worth it, given the age and mileage on the P.

v71 and v113 are showing 005 fault code
•	I’m not surprised that the v71 and v113 are both failing intermittently. These two are the only sources of air input to the system. This explains why I sometimes get airflow and sometimes not.
•	v71 is easily accessed under the hood. 
•	v113 is this one easily accessible?

v205 showing 014 fault code
•	My driver side dash vent near the window doesn’t have airflow. The electronic flow adjustment doesn’t respond. In the schematic listed above in the thread, this looks to be v206. I’m surprised v205 is the one failing. The passenger far right dash vent seems to work fine. I’m assuming Left means Driver’s side.

v213 showing 014 fault code
•	Dash-top diffuse vent. How difficult is this to replace?

v108 showing 014 fault code
•	Driver's side footwell. This means cold feet in the winter. I hope this isn’t buried in the dash.
____________
v107
•	Defroster. This is not showing an error, but I can seem to get the defroster to turn on. 


Many thanks in advance....Bob


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## invisiblewave (Sep 22, 2008)

Let me know how easy it is to get to your V71. Mine isn't working, but it looks to me as if the cover at the bottom of the windscreen needs to come off to get to the V71 which is what has stopped me doing the job so far. I don't think adaptation is going to help. I don't recall if it's the V205 or V213 I looked at, I did the one above the glove compartment. It's relatively simple to get to it, once the glove box is out, it's right there. However, mine shows bad adaptation, even though I can watch it moving without a problem. As far as I can tell, mine works despite throwing a code, so I haven't changed it.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

sachverhalte said:


> Hi All,
> 
> I'm having intermittent air flow issues on all functions. The defrost function doesn't work at all. The VAG shows errors on several flap controllers. The first step was to replace the driver's side battery with a new OEM model. It didn't seem to help. I'm hoping one of the more knowledgeable forum members can help. On 005 fault codes seems to indicate a need for part replacement. Does the 014 fault code just call for a new adaptation routine?
> 
> ...



Did you try resetting the faults?

Are any of the faults intermittent?

Has your left battery ever been low since the last DTC reset? 

EDIT: I see the left battery was replaced. After that, it might take several DTC resets to get back to "normal" again. I think it took about 3 or 4 resets before mine "only" showed the hard faults that won't clear. 

I also keep the engine running during scans so my battery won't drain. 

Before trying anything else, I would reset faults. It's basically free to try. 


-Eric


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## Bindaham (Apr 4, 2014)

Did anyone dig that V212 motor out, or have the instructions on how to do so?


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## Bindaham (Apr 4, 2014)

Yet another peculiar A/C issue. I got used to one side cooling but recently I noticed that cooling is not the same in the same side or in comparison to the rear vent even if it's the same said.

I also noticed unusual heat from the lower driver side center console close to my right leg calf which I believe it's where the heat exchanger is, while it's normal in the same position of the passenger's side.

The front and back left side vents blow hot air while the front right side is much cooler and the rear right vent is the coolest of all.


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## gottarideduc (Oct 28, 2015)

I had the same problem. The air temp at the center rear outlets as reported by the scan tool was as much as 8 degrees C different. Turned out to be low refrigerant. The car has had a tiny refrigerant leak issue since it was new. Nobody has been able to find the leak. For the Climatronic to do its job, the cooling circuit must work correctly.


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## Bindaham (Apr 4, 2014)

Thanks for the reply


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## Phaetonlvr (Feb 26, 2013)

I just had the exact same problem as the OP and figured it would be good for future readers of this thread to add some more detailed info on this issue. Cooling on the left side was insufficient but ok on the right, no fault codes, evap temps in the single digits, however when I logged Controller 8 (HVAC) data on my typical drive to work I noticed that the refrigerant temperature (AC Compressor discharge temp) would go as high as 110 C. This is too high and can degrade the oil in the HVAC system. Reading up on this issue I found that the typical reason for the high refrigerant temp is a low refrigerant charge where there is not enough refrigerant to absorb all the heat. This combined with previous posters on this thread, confirmed for me that this is indeed a low refrigerant situation but just not low enough to trigger the "low refrigerant" fault.

So I went ahead and added some clean R134a without any leak sealer to the system using my AC manifold gauge set. This went pretty well and I think I got to the right amount by monitoring the MVBs while charging the system. I logged the data while I did this and put it in a trend chart afterward which makes it really obvious that low refrigerant was the cause for this issue.

Here's a screenshot of the chart, you can see that starting at timestamp 209 (bottom) I switched on the AC and started adding refrigerant. The left hand vent outlet temp started dropping accordingly until it came down to the same temp as the right hand vent and the refrigerant temp also dropped as was expected. Then they started dropping together. I added a little more to the system until the evap temp was at around 2C. Now I'll have to log some data on my drive to work again and compare to the old log.


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## action2020 (Oct 12, 2005)

*Unexpected findings (ac flap, cooling one side only, related stuff ) blower motor resistor*

I just have to post my findings on this issue that resulted in some unexpected and easy results to what started it all with a notion that some vent flap(s) got stuck that caused only cool air to come out of one side of the air vents (whether it is/was the left or right side). Solutions/suggestions I looked everywhere (blogs, dealers, mechanics, etc) pointed to doing something to unstuck the flap(s) which appeared to be a hell of a job (including but not limited to opening up the dash potentially, to something as simple as cutting the backwall of the inside of the glove compartment where there's a pre'perferated rectangle shape that allows you to reach into it to possibly touch/unstuck a flap arm or something or other.. All of these routes appear to be kind'a hell'ish, expensive, not feasible, and/or a major headache.. until I did this:

1. replaced the ac blower resistor (which involves cutting the inside backwall of the glove compartment to get to the 2 screws that secures the 'blower resistor' (this is a light blue thing you'll see right away if you decide to cut out the rectangle. It's not that easy nor hard to do, but if you have a dremel with a sanding drill bit (what looks like a tooth pick bit with a rough surface for sanding) use this to poke holes just deep enough to penetrate the plastic wall (don't go in deep! cuz there is a wad of cables directly behind the plastic wall.. you DO NOT want to damage those cables with your dremel or whatever knife/sharp tool you'll use to cut the back wall of the glove. Look carefully and you'll see the perferated subtle lines . Do not use a sharp blade or exacto knife cuz the plastic is just too thick .. Dremel tool with the tooth pick shaped drill/sanding bit works miracles. After you've poked holes with your dremel bit, with holes a few milimeters apart, then just gently force the dremel to pull/cut through from one hole to the neck hole. It's so easy this way, and you'll get a fairly precise cut.

2. to remove the resistor, this will look impossible when you look at it, cuz the wad of cables are blocking the resistor's way to come out. The trick is this: gently pinch the two square very small column looking clip release and the pull from the [ and ] shaped plug handles you'll see on the plugs. Not too much force if you pinched the release, the plugs will come out.. And then, just wiggle the two plugs outta the way. This step is essential to get the resistor out. You'll have sufficient space to angle/wiggle the resistor out.

3. BE VERY CAREFUL to not drop the two screws inside of the back wall, as you losen it.
4. Best to use a socket that attaches to a screw driver handle. Preferrably with magnetic power to hold the screw from falling. What I did was (as a safety measure, I even covered the screw head with a tiny double layer of food plastic wrap, so that the screw head gets stuck on the socket as I losen it, so that there's less of a chance the screws will fall into the abyss.

5. Put the new resistor in place, in reverse order. It's actually all not very difficult and surprisingly easy (if the size of your hand isn't an issue in the space you have to work with).

The touareg blower motor resistor for the years 2004-2010 or whatever this model is for:
http://www.partsgeek.com/catalog/2004/volkswagen/touareg/climate_control/blower_motor_resistor.html
may apply to other touareg or audi Q7 models.
$125 on partsgeek but can be gotten for $30 to $50 on ebay brand new.

Ok, now for the unbelievable and unexpected findings after I replaced the blower, the flap issue also got fixed. The flaps no longer struggle, no long make a repetitive clicky noise, and both vents are blowing cool air.

So, my conclusion in my case: the flaps and the blowing of cool air on only 1 side, were caused by faulty electrical currents as a result of a crappy resistor part that came w/the touareg. My 2004 touareg started making the flap click noise as early as 2006 . but the dealers never ever wanted to fix it, and even pretended they don't hear the noise .. 

What happened in my case was that one day, my ac fan went to maximum blow levels on its own.. And when i turned off my engine, the fan still kept running full blast.. This freaked me out so I had to just pull the fuse to stop it. The fuse is on the left side of the steering wheel if you know where the fuse box is. The very top large block orange fuse is the one.
I looked it up and found out that the resistor must've gone bad; that's why the blower won't stop even when the car is completely turned off. And guess what? This fix not only fixed my defective blower resistor, but my flaps now work smoothly with no clicks .. like new. This is a much welcomed result!

part # of the resistor: 7L0907521 or 7L0907521A or 7L0907521B

works for audi Q7 .. porsche cayenne .. vw touareg .. just double check the model years of your Q7 Cayenne Touareg .. 

Have a great day..










Sealed it with Gorilla tape ..


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## Paximus (Aug 26, 2011)

Thank you to both of the previous posters, both Stephan and action2020.

The a/c information is very welcome, because we would otherwise have a fixation on flap motors and controllers when the root cause is somewhere else.

The Touareg has essentially similar technologies to the Phaeton, so if anyone cares to confirm that the P has such a resistor somewhere then that would also move us further on. 

Chris


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## invisiblewave (Sep 22, 2008)

Interesting stuff indeed! Rather than cut the glove box, though, I'd be inclined to remove it, it's not too difficult, just fiddly.


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## Gabs08PHTN (Jan 6, 2011)

Paximus said:


> if anyone cares to confirm that the P has such a resistor somewhere then that would also move us further on.


Is not that the resistor that sits by the HVAC blower in the plenum?
If that is the case, I think that can be accessed after removing the HVAC housing front cover.

Gabriel.


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## action2020 (Oct 12, 2005)

*the inside backwall (plenum) of the glove box was designed and pre'perferated to be cut*

Cutting the inside backwall (plenum) of the glove box was a designed step .. It seems that the VW engineers knew that the resistor would go bad one day and need replacement, so they put the perferation there so that cutting out the rectangle shape opening would be easy and fairly precise ..

To remove the entire glove box for the purpose of replacing the blower motor resistor might well be more of a chore than the cut out method .. IMO ..


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## action2020 (Oct 12, 2005)

*the blower resistor is located directly behind the perferated rectangle shape on the backwall (plenum) of the glove box*

the blower resistor is located directly behind the perferated rectangle shape on the backwall (plenum) of the glove box .. 

once u cut out rectangle shaped plenum (with a dremel drill bit by first drilling/poking a series of holes about 3mm apart .. and then pulling the drill bit across the holes to cut thru .. drill no deeper than once you've penetrated the thin plenum because there are cables behind it touching the plenum!) you'll see that the resistor (light blue thing with 2 screws) is right there, and best accessible from that rectangular hole that you just cut out .. IMO .. must remove the two plugs gently first in order to wiggle out the resistor at the proper angle to pass it thru the wires .. looks harder than it really is .. it took me a minute or less to wiggle out the resistor once the screws are removed, and plugs unplugged .. careful to not drop the 2 screws of the resistor ..


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

action2020 said:


> the blower resistor is located directly behind the perferated rectangle shape on the backwall (plenum) of the glove box ..


Is this on a Touareg or Phaeton?

As invisiblewave pointed out, removing and replacing the Phaeton glove box is fiddly but not terribly difficult. That's if the resistor is even behind it. 

I honestly don't remember on mine because I removed the glove box to get rid of some crap wiring from a hidden radar detector. 

If anybody wants to know how to remove and replace the glove box I can guide them. The Bentley has the correct method but leaves an important step out. It also tells you to take stuff apart or out that can stay put.

The wiring is the hardest part. As you said, you sure don't want to damage it. 


-Eric


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