# Air Conditioning Blowing, but Nothing Coming Out of the Vent???



## wetsiderkg (Dec 28, 2012)

Sorry if this is in the TOC, or searchable…but I couldn’t locate a answer. So I started the car this morning and for the first 10 minutes the AC on Low Temp setting sounded like it was blowing hard on the highest setting, but almost zero air was passing through the air vent? After 10 minutes, without warning, the air finally started coming out of the vents, with a audibly noticeable difference in tone? Anyone else have this problem?


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## Paximus (Aug 26, 2011)

Hi (sorry, I don't know your name),

Although this could be a face-value A/C flap problem, it is the kind of gremlin that happens when the left battery is aging and the controllers find their power supply momentarily dips below spec at start-up.

Repairs to some of the flaps in the HVAC assembly are quite labour-intensive, so if there's any suspicion that the batteries are older than 5 years it's worth investing in new ones before spending too much time and money fault-finding unexpected behaviour.

If you are confident in the batteries then the next step is to do, or have done, a diagnostics scan.

Chris


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## wetsiderkg (Dec 28, 2012)

Thanks Chris. The battery is less than 1 year old. Will run a scan today to see. - Randy


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## mik15 (Dec 18, 2012)

had a similar problem today, started the car in the morning around 9AM(35C here), went out to do some things everything worked ok, came back, parked the car in the garage and 1 hour later i had to go out again, started the car and the blower would only work intermittently and i couldn't hear the AC compressor coupling and neither the cooling fans, so left the car parked and went out by foot to a place nearby to get things done....i was really pissed off as it couldn't have chosen a worse moment to do this(summer is very hot) so i went later with my VCDS to check for errors and when i started the car everything worked ok as nothing happened! Looked for codes and i had a long list of intermittent codes on HVAC unit and one of them was from the N280 valve which i guess triggered the others, that must've been why the compressor wouldn't start and therefore the blower would go on and off....i guess it's just one of the gremlins haunting this cars...hopefully it doesn't come back


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## PanEuropean (Nov 3, 2001)

Mike:

Although it is possible that you have a problem with the valve that you mentioned, do keep in mind what has been mentioned above, which is that low voltage on the left battery can cause a great variety of 'spurious' fault messages (and actual faults) to appear. Broadly speaking, this happens because some controllers are more sensitive than others to low voltage conditions. Those low voltage conditions could be momentary (for example, during or after starting), or persistent (low voltage on the left battery caused by short driving cycles or the battery reaching end of life).

So - the moral of the story is this: If you are suddenly confronted by an unusual fault in an otherwise satisfactory vehicle, be certain to rule out low battery voltage as the cause before you go digging deeper into the problem. The easiest way to rule out low battery voltage as the cause of a problem is to charge the left battery up overnight using a battery maintainer. There is a post here in the forum that explains how to do this, here is a direct link to it: Purchasing and using a Battery Maintainer for your Phaeton.

I often go out of my country of residence for a month or more on business. Even though I have relatively new OEM spec batteries on both sides of my car, I *always *connect the battery maintainer and charge the car up overnight the first night I am back at home. I have learned that this is 'for sure' the simplest and easiest way to keep my (infrequently used) Phaeton operating trouble-free.

Michael


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## wetsiderkg (Dec 28, 2012)

Ran the code last night (see below)


Address 8, Auto HVAC, 01274 Air Flow Flap Defective & 00445 Refrigerant Loss


Any recommendations? Its at the stealerships today.

Randy


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## PanEuropean (Nov 3, 2001)

Randy:

Normally the diagnostic scan will identify the specific flap that is not operating properly. Are you using a VAG-COM (VCDS) scan tool, or a different brand of scan tool?

Michael


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## Paldi (Sep 4, 2004)

This issue visited my car a few times, maybe 3 - 5 years ago. In my case, I was just starting out after the car was parked overnight or had been sitting for several hours parked. I discovered if you stop the car for 5 - 10 minutes and "walk away" the problem resolves by itself. With a little luck, your issue will resolve too.

My batteries are now 8 years old. No electrical issues that I know of except an occasional mysterious opening of the sunroof while driving. (Knock on wood.)

Fred


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## wetsiderkg (Dec 28, 2012)

Michael:

Yes, VCDS pulled the above mentioned codes. Will be interested to see what the dealership says, but I would think either the compressor is not engaging or there's a pressure loss somewhere in the line? Thoughts?

Randy


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## Tiger0002 (Apr 23, 2013)

Perhaps your description of event is confusing to a lot of people including me. At first, you seem to be describing the air flow problem then you didn't state when this started to happen... at the beginning when you start the car up or during middle of the trip after x amount of minutes...

You did not state whether the air was cool or ice cold at each given time... whether it was wet feeling or dry...

Sounds like you got evaporator icing going on... due to low refrigerant level. And at some point, compressor shuts off and evaporator deiced and starts to blow cold air again... but this cycle should repeat itself during the trip or short lived... perhaps you didn't drive it long enough to fully comprehend the exact problem... like you only drove 15 minutes at a time.

Anyway, it helps to start the discussion with very detailed event description.


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## PanEuropean (Nov 3, 2001)

Hi Randy:

It appears to me that you have two entirely different and unrelated problems, although both problems affect the same system (air conditioning).

The 'Refrigerant Loss' fault is pretty straightforward and doesn't require any interpretation - it means that the pressure of the refrigerant in your system is below normal. To solve this problem, two things have to be done: First, the source of the leak must be found and fixed, and second, the refrigerant charge needs to be brought up to specification. God only knows where the leak is (unless there is some obvious clue, such as damage to a refrigerant line). The leak could be at a connection, in the compressor, in the evaporator (which is buried deep in the middle of the HVAC system in the center of the dash), etc.

My suggestion is that you first resolve the leak and recharge the system, then, once that has been done, determine whether the 'flap' problem is actually impairing the function of the heating and air conditioning system. I still don't know which of the 20+ flaps it is that is reporting a problem. If it is the flap that divides airflow between the footwell and the mid-level pillar for the left rear seat, you might well decide that it is just not worth the time and trouble to repair it, because that seat is rarely occupied.

When you next run a diagnostic scan, please copy the results from VCDS to a text file, then, post the complete excerpt from that text file that pertains to the HVAC system so that we can see the actual VCDS report. The VCDS report contains additional detail about the flap that you have not posted so far.

Michael


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## wetsiderkg (Dec 28, 2012)

Here is the actual code Michael. Any help with isolating the problem would be appreciated since the dealership is proving less than helpful and there are only 3 in the area (already been to 1 of the other 2....nice people, but again...not helpful). Thanks! Randy



Address 08: Auto HVAC Labels: 3D0-907-040.lbl
Part No: 3D0 907 040 G
Component: Climatronic D1 1144 
Coding: 0000001
Shop #: WSC 00000 000 00000
VCID: 224B0902FE755B0816F

2 Faults Found:
01274 - Air Flow Flap Positioning Motor (V71) 
014 - Defective - Intermittent
00445 - Loss of Refrigerant 
000 - - - Intermittent







THIS IS THE ONLY OTHER CODE PULLED....UNRELATED CODE I THINK....


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Address 09: Cent. Elect. Labels: 3D0-937-049-V1.clb
Part No: 3D0 937 049 G
Component: STG.Bordnetz 5001 
Coding: 0000003
Shop #: WSC 22231 444 54614
VCID: 2E53ED32BAADEF68827

1 Fault Found:
00907 - Intervention load Management 
000 - -


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## PanEuropean (Nov 3, 2001)

Hi Randy:

The V71 flap motor is the motor for the primary air intake flap. Because this fault code is 'intermittent', I suggest you clear the code (after saving a copy of the report) and wait and see if it comes back. I've posted a picture of the flap motor location below - it is the uppermost item on the illustration. Fortunately, this is an easy part to replace, if in the future it does need to be replaced.

It is very unusual to see a 'loss of refrigerant' message appearing as an intermittent fault. My guess is that the car just had a momentary hiccup, because what that message is telling you is that there was a low refrigerant condition in the past, but that condition is not present now. So, unless someone refilled your AC system in the middle of the night (not very likely), that fault is probably spurious. Again, clear the code, and monitor things to see if it comes back again. In principle, if the AC system works (if it cools the car), don't worry about it.

The 'intervention load management' code can be disregarded. That is not a report of a fault, it is just a report that at some time in the past, the car shut down certain electrical services for a period of time to conserve energy. It might be as simple as turning off the trunk light if the trunk was left open for more than 10 minutes. That message almost always appears on diagnostic scans, and unless you have some kind of electrical problem present that you are troubleshooting, it can always be disregarded.

Michael

*HVAC System Components*


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## wetsiderkg (Dec 28, 2012)

Michael,

Thanks so much for the schematic! I will take that to the dealership today to show them. 

Unfortunately, I've cleared the V71 code 3 times now and it continues to return. 

It’s very hard to be patient with the dealership at times, wish me luck.

Randy



UPDATE - Dealer installed a new V71 motor to the tune of $600. Expensive, but it works like a charm now.


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