Originally Posted by veedubb

Ever since I bought my B6 two years ago, these flap motors have been driving me crazy. For some reason, Audi didn't wire the HVAC to the ignition switch so these motors keeping whirring and cycling away when the potentiometers (pot) aren't sending the right voltages to the HVAC unit even when the ignition is turned off.

This is caused by the pots (contained inside of the motors units) accumulating dust that prevents proper readings (dead spots). Aside from replacing the motor units, the best fix is to remove each one and clean the pot contacts.

VAG-COM codes I pulled to determine which motors are acting up:
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Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 L
Component: A4 Klimaautomat 1116
Coding: 00000
Shop #: WSC 63351
VCID: 2A50CA3CD6B1254EEA7-513C

2 Faults Found:
01272 - Positioning Motor for Central Flap (V70)
41-10 - Blocked or No Voltage - Intermittent
00604 - Potentiometer Positioning Motor for Air Flow Flap (G113)
30-10 - Open or Short to Plus - Intermittent
-------------------------------------------------------------------------

V70 is the Air Flap Control motor assembly mounted on the blower motor housing behind the glove box. It's the one with the light blue wheel. Since I was in there, I decided the clean the other (Air recirculation flap control) motor assembly too since it's right beside it.

It's relatively easy if you are handy. Here are some of the tools you need:

- Digital Volt Meter (DVM)
- Precision (Jewelers) screwdriver set
- Isopropyl (Rubbing) alcohol
- Cotton swap (Q-Tip)

Remove the glove box and motor assembly from the duct work. I won't describe it here because it's self explanatory. If it's not, you shouldn't even be attempting this procedure yourself.

Make sure the motors have stopped completely before you remove them. This is so you can put it back later and have everything lined up in their resting positions. Again, this may take a while because they have a mind of their own, even with the key removed from the ignition.

The hardest part is getting inside the motor assembly. It just takes patience and a light hand.

*** WARNING: It's very easy to break the motor assembly tabs so be careful. ***

I have found that it's easier to attack the smaller tab first (see Pic). Once this is separated, un-clasping the remaining tabs should be a cinch.

Once the half casing has been removed, you can see the motor, gears and the pot (see pic). Before you do anything, mark the pot's initial position (see pic) so you can put it back in the same setting when re-assembling.

Now carefully pry up on the pot to remove it from the assembly - it should pop out very easily.

Since this is a center tap pot, meaning the center pin is the varying part of the resistor, one side's resistance is the difference of the other side (see pic). You'll figure this out when you play with the measurements. Across the outer pins, it's should be fixed at 5Kohm. Each leg with reference to the center should read between a couple hundred ohms to about 5Kohm.

To check for dead spots in the pot, simply measure the resistance across the center pin to one of the outer pins while SLOWLY turning the pot one way or the other. Once you get a reading, keep turning slowly and you should see the meter jump around if there are dead spots. If you're using a digital meter, it may read OL or something like that because it's telling you that you're measuring an open circuit.

Now clean the pot (see pic). With a very small precision screwdriver, pry the pot open (be careful not to pry too much or you'll break the pot) and take a cotton swap soaked with rubbing alcohol and rub it into the crack. You don't need too much rubbing alcohol, just enough to get a drop inside of the pot. Now give it a shake to saturate the inside with it and turn the pot a few of full turns each way to work in the rubbing alcohol. Don't do this too fast as you may induce additional wear on the pot.

Once the rubbing alcohol has been worked in, let it dry a bit and measure the pot again. If done properly, it should give you a nice continuous reading between the center and one of the outer pins.

Now measure the other outer pin and you should see the same smooth continuous reading. There shouldn't be any dead spots now unless the pot internals has completely worn away. If this is the case, there is no other choice than to replace the whole unit.

If all your post cleaning measurements are good, re-assemble the motor assembly but make sure all the pins on the pot are lined up straight (not bent) with the motor pins. This will ruin your day if you plug it back into the car and bend or break the pins if they're not lined up.

The last step is to re-calibrate the motors so your HVAC unit can get a handle on the new readings. You may or may not need this last step but if you have access to VAG-COM, why not?!? You might as well clear the old HVAC codes while you're doing the calibration.

See this VAG-COM calibration taken from another post (not mine):
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Ok, I managed to find the basic setting for all the flaps.
It's located at:

Controller 08 - Auto HVAC
Basic Settings - 04
Group 001
Go!

There are about 10 values that come up but around 6 of them go through a cycle. You can hear them all moving to the upper range and find their limits and then they all move to the lower range and then they all reset back to 0. This takes about 60 seconds.

The aircon stops while it's doing this and starts up again once completed. I went back into the Fault codes and it now shows No faults.

Seems to have worked but I will have to put it to the test tomorrow when I drive the car to work. I'll update as to how it went, if I hear any more noises or if the fault codes come back up.

Had same issue and was able to clear it by using Ross Tech to go to AC module - basic settings and having module perform a recalibration. took 2 minutes to move all flaps to min and max and find new zeros and then the noise and codes have been gone for 2 days now!
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Good luck!

I'm trying to help other Audi owners with my own experiences, so if you find this post is of any value, please let me know with a response or a PM. It's only fair because of the time and effort it takes to do a proper write up. In other words, if I don't know my contribution is helping others, I may not have the incentive to post additional fixes.

Thanks.

Originally Posted by veedubb

It's been a week since I did these flap units and so far so good. When I went to re-calibrate the motor flaps with VAG-COM, I found another one that needs attention:

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Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 L
Component: A4 Klimaautomat 1116
Coding: 00000
Shop #: WSC 63351
VCID: 2A50CA3CD6B1254EEA7-513C

1 Fault Found:
01809 - Actuating Motor for Temperature Flap; Left ( V158 )
41-10 - Blocked or No Voltage - Intermittent
----------------------------------------------------------------------

Needless to say, I needed to get this resolved as well. So I removed the drivers side knee panel and took a look at it. I wasn't too impressed at where it was located. It looked like a PITA and after spending about 3 hours, it ended up to be a PITA.

I had to remove the accelerator pedal which is held in with 3 hex bolts (size: 5 mm). You may be able to remove the motor unit without removing the accelerator pedal but I doubt it. There's 2 up top and 1 at the bottom. The hardest one to remove was the upper right one.

The flap motor unit has a red arm and held in with 3 screws (6mm) much like the other motor units described before. This is pretty challenging as well because there's no space to work under there. Once the screws are removed, the red arm is still attached to the flap arm so you need to line up the key slots before you can remove it (see picture).

*** Again, make sure you know the position of the flap arm before removing the motor unit so you know how to re-assemble it properly. ***

Once you remove it, the same procedure applies to clean the potentiometer inside the motor unit as described before. FYI, this pot's value is approximately 4.3Kohm if you really needed to know.

It's a lot of work and lots of knuckle scraping but in the end it works very well if you are willing to put in the effort, especially this particular one.

I'm willing to bet that my AC and heater will work better after all of this because these damn flaps won't be bouncing around opening and closing when they want to.

Other than the noises they make, I haven't had decent heat in the winter nor decent cold air in the summer so I'm pretty confident these fixes should bear fruit.

Originally Posted by ddarziu

I have the exact same problem on my Audi A4 B7. My question is, how did you clean the pot on the Actuating Motor for Temperature Flap; Left ( V158 )? As can be seen in the pictures, it's encapsulated and I don't think it's possible to pry it open as you've done with the pot from your first post.
Any advice on how I might be able to clean it up?

Originally Posted by veedubb

Hi. I did it the exact same way as the others. I don't remember it being any different than the others if yours is the same type in my pictures.

It may be a possibility that Audi had changed it in the B7. I know that they do change even the smallest things from one year to the next. I.e. rear license plate light strip on the trunk (boot) was changed from metal in my 2003 B6 to a plastic strip in the 2005 B6.

Sorry that I can't help if this is your case.

Good luck though!