# HVAC blower wont turn off??



## zenmoused (Nov 6, 2008)

Hey guys, I have a problem that's sprung up all of a sudden and I wanted to run it by you before taking it in to VW. For the past three days or so the blower on my Phaeton's HVAC has been unresponsive to my control, staying on its highest setting permanently, even when I turn off the car. This of course means that overnight power management takes over and when I get to the car in the morning I have to unlock it with the physical key, the clock has to be reset and I get all kinds of warnings about level fault and system fault. These warnings go away immediately as the car powers up, and everything is back to normal except for the fan.

I've tried resetting all settings on the control unit, but since the fan stays on even when the car is off, I feel like it's not software? The rest of the HVAC settings seem to work fine- I can toggle the vents and change the temperature, just not the blower speed.

Anyone have this happen to them? My Phaeton is out of warranty so I'd like to have some ideas for the technician to narrow it down. Thanks in advance for any insight!

Brian


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## johnt26 (Dec 3, 2009)

I'm still getting my feet wet in the world of Phaetons and lurking so I know less than nothing .
However, in the world of high tech aircraft sometimes we re-boot the system by removing power for a minute and re-powering or the mechanic "re-racks" the problematic circuit board, many times that solves the issue (no, not while we are actually flying!).
Maybe a disconnect/reconnect of the AGM battery? I assume that is what runs the HVAC fan? What do the guys that know the vehicle/systems think?
Best of luck,
John


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## zenmoused (Nov 6, 2008)

Thanks John, 

That was my thought, since I've had similar success with my other cars doing a "hard reboot." I hesitate though since the Phaeton has the complexity of a space shuttle, and I've heard quite a few stories on here of funky things happening when people disconnect their batteries. Also I'm not sure how to even go about it, since the car has two. Has anyone else done this?

Brian


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## Prince Ludwig (Mar 24, 2007)

There aren't any major consequences from disconnecting both batteries (I did it this weekend!). The two things that will happen are the ESP light will come on saying that it's lost the steering angle sensor. However, it should go out after a short drive and, after checking the sensor using a VAG-COM, mine still shows 0 degrees when the wheel is dead-ahead. You may also get a "Level fault - Workshop!" warning but that vanishes after raising and lowering the suspension.

The control modules will probably record various power supply faults as a consequence of disconnecting the batteries but none of them will affect functionality.

Harry


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## zenmoused (Nov 6, 2008)

Thanks Harry! If you don't mind, how did you go about disconnecting the batteries? What order did you do it in? I know how to get to the trunk battery, but I'm afraid I'm not familiar with how to disconnect the other one. I'm going to take a gander at the table of contents, where I'm sure Michael has some incredibly detailed writeup haha.


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## Prince Ludwig (Mar 24, 2007)

I started by disconnecting the negative terminal on the right hand battery followed by the negative terminal on the left hand battery then the positive terminal.

Harry


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## mhoepfin (Dec 20, 2007)

Have you tried just pushing the Reset button on the infotainment console?


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## zenmoused (Nov 6, 2008)

I have tried that, to no avail. That was my first thought, that it was some setting that got messed up. No such luck. I'll try disconnecting the batteries this afternoon and report back.


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## kend414 (Feb 10, 2009)

Have you tried slowing down/shutting off the fan speed from the rear console (if so equipped). I understand that the rear console fan setting overides even the front controls. I never understood this feature. You could also pull the fuse to the fan before disconnecting the batteries. Good luck.


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## zenmoused (Nov 6, 2008)

kend414 said:


> Have you tried slowing down/shutting off the fan speed from the rear console (if so equipped). I understand that the rear console fan setting overides even the front controls. I never understood this feature. You could also pull the fuse to the fan before disconnecting the batteries. Good luck.



Yeah I never understood that either. It's my least favorite function of the car, since there's no child lockout. I took your advice of trying to pull a fuse, however I wasn't sure which one controls the fan. I pulled 4 or 5 with no effect. 

Anyway it seems I won't be able to undo the battery today after all, thanks to the joy of working from home and having an 18-month old who is allergic to naps. Thanks for the ideas guys, I'll keep you posted.


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## zenmoused (Nov 6, 2008)

Well, disconnected both batteries, all settings were reset, blower still on max. I'm starting to think maybe it's the blower's controller? If it were hardware, like a short, the power management system wouldn't be able to shut it off. If it were a software preference, it would have been reset. Does that seem right?


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## PanEuropean (Nov 3, 2001)

This might be a little late in the game to suggest, but:

Have you tried pressing the AC hard-key, then the RESET key?

Michael


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## zenmoused (Nov 6, 2008)

Thank you for the suggestion, Michael. If you mean the key marked "climate" and then pressing the "reset" button, I have done that three or four times now. I'm sure that once I bring it in they will be able to isolate the problem immediately with a scan tool, I just question the abilities of my local VW repair guys, since they've been wrong quite a few times. Also I'm a bit wary to drop off my car since it was broken into the last time I left it at a dealer :-/

Brian


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## zenmoused (Nov 6, 2008)

*The plot thickens...*

Haven't had time to go to the dealer yet, but something interesting happened this morning. I fueled up completely, and when I got back in the car, the gas needle didn't budge from its place at 1/8 tank. By the time I got home about 15 minutes later, it had incrementally risen to the 1/4 tank mark, just very, very slowly. It would be quite a coincidence for both of these things to happen independently of each other, so I'm left wondering what the fuel sending unit and the blower have in common?


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## PanEuropean (Nov 3, 2001)

Before your VW dealer does anything else, please ask them to check the software version in your instrument cluster (controller 17) and see if it ends in the number '21', such as 0321, 0521, etc. 

If it does not, get the software in the instrument cluster updated in accordance with the TB for doing that, which is discussed in detail at this post: TB: Distortion in the Display Unit in the Instrument Cluster (MFI, or Y24). 

As I think most of you know, I am very reluctant to criticize VW, but in this particular case, I think it was very wrong of VW of America to have not made that software update an obligatory campaign that was carried out at the next oil change, as was the case in all other world markets except for the USA and Canada. 

The instrument cluster contains the router for all of the various CAN and fibre-optic networks, and that software update specifically addresses problems that can arise in passing information across the various networks. 

Michael 

PS: I think you will eventually find that your fan control problems (and the fuel indication probem for that matter) have nothing to do with the fan, instead, they have something to do with a malfunction on one of the CAN bus networks.


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## zenmoused (Nov 6, 2008)

Thank you Michael. I'll give them a call and make an appointment. It's really a shame I didn't have this done while my car was still under warranty.


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## zenmoused (Nov 6, 2008)

I have been super busy and haven't had the chance to take the car in yet, but I was able to recall the exact series of events that led to this blower problem. I got into the car to move it a few feet so someone could get out of my driveway. I turned it on for a split second, then for some reason changed my mind and immediately shut it off. Clearly this is not an advisable thing to do to a car, but that's exactly what triggered it. After that the blower has been running non-stop.

So I'm left wondering if it's something that maybe a battery reset will fix, though I'm still not 100% sure of that procedure. My first inclination was to check fuses, but I haven't been able to find the one that controls that blower. I hooked up my cheapo vagcom for a minute today and got a fault code saying "faulty fresh air blower." From reading the ross-tech site, this could be literally the blower, the controller module, or the climatronic module. I just feel like I messed up the software of the car rather than actually broke anything.. anyone have any ideas for me before I bring her in? My hesitance here is that I use her as a daily driver and my local dealer doesn't do loaners, so I'd be renting a car on top of paying out of pocket for any repairs. If there are things I can try myself or at least a direction to point the tech in to save time, I'd like to try those first.

Thanks again for any thoughts.

Brian


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## PanEuropean (Nov 3, 2001)

Hi Brian:

I think that this is a situation such that you really need to run a diagnostic scan of the car and see what fault codes are being reported. For example, if the car reports that the HVAC controller (controller 08) is defective, then the solution is pretty straightforward - that controller will need to be replaced. Likewise, if the car reports that the fan blower motor has problems, then that is the component you need to fix.

You should also carry out functional tests on the HVAC system by initiating these tests with the diagnostic scan tool.

It is also possible that you might be able to reset the HVAC controller by entering a value of 00 in adaptation channel 0 of that controller.

Michael


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## zenmoused (Nov 6, 2008)

Michael,

Thank you again for your suggestions. I'll give the adaptation a try and if that doesn't work I'll bite the bullet and bring her in. It's getting really annoying having the power management kick in every time I park.

Thanks,
Brian


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## PhaetonV10-EST (Nov 5, 2011)

My HVAC blower recently died.
1. I bought a second hand blower regulator, since it was the most likely fault. No cure.
2. Changed the blower, and it started right up. Even if it was supposed to be OFF.

I then disconnected the blower regulator, hoped that its faulty, but still blower kept going.
When everything else failed, i laid my shirt on top of the solar roof, that stopped it.

The solar vent option doesnt seem to obey to what is chosen from the infotainment display 

Anyone had the same problem?

I cant think of anything else then a faulty HVAC controller.


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## zenmoused (Nov 6, 2008)

I forgot to come back to this thread and update- I took mine in with the same symptoms and it ended up being the blower controller. It wasn't a cheap fix unfortunately..


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## burninginflames (Apr 23, 2010)

Was the blower controller this?

3D0907521









Just had the same issue after getting my compressor cleaned and this is what the dealer diagnosed.

Hope it works!

Respectfully,
Jacob Benkovski


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## Phaetron (Oct 6, 2012)

Has anybody ever figured this out? I've been dealing with this problem for the past six months. my repair shop couldn't figure it out.


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## pgoober (Jan 4, 2009)

*My read was OP solved problem with new control module*

Phaetron,
OP seems to solved problem with controller replacement.
Michael indicates it should be visible as controller 8 in post#18.

I presume these are not your issues since your shop likely scanned the car, but it might be worth asking if the scanner can "see" the controller.

Which version of the P is blowing you away (Model in the profile makes it easy to tell)?

-BD


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## burninginflames (Apr 23, 2010)

Phaetron said:


> Has anybody ever figured this out? I've been dealing with this problem for the past six months. my repair shop couldn't figure it out.


Hey Phaetron,

I bought a new controller, just like the one pictured, at a junk yard. Swapped it out and the problem was fixed instantly. Apparently when you wash the engine, water can get into the controller and short it out.

Respectfully,
Jake


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## Kuwaity (Apr 2, 2004)

This happened to me too. I bought a new controller, but just before installation, the blower went fine by it self!

You better wait a bit and see...


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## mattyprice4004 (Jan 2, 2018)

I realise I'm bumping a very old thread - but I found this thread several times while trying to solve the issue of my blower being totally dead.
The connection between blower and transistor pack had allowed some water in - after a good contact cleaning and reconnection, everything behaved again.

You can get your fingers down the fresh air vents to disconnect the blower and apply switch cleaner - then connect and disconnect a few times to make a good connection.


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