S6C4 Center Air Ducts with no flow .

[Harvester]

Hello ,

I have a problem , only ducts on the sides on the window and on foot are working , the biggest in the center is without flow . Climate control works , I tried another one , where should be problem ?

Thank you very much .

And I have another one problem . Air ducts should be iluminated on S6 C4 , or not ? Im not sure , but mine doesnt light .

Thank you again

[shaun5]

Sounds like you might have faults with the stepper motors. UrS4boy will be along soon and put some links up or you should search climate control faults. The actual display tells you fault code. Do a search

[UrS4boy]

UrS4boy will be along soon and put some links up or you should search climate control faults.

I will later. For now, I am too busy checking my ego at the door.

And going out for lunch with my wife.

Chus bis spater.

[UrS6 - IamS6]

I will later. For now, I am too busy checking my ego at the door.

And going out for lunch with my wife.

Chus bis spater.

Best get this reply posted while you're away from the keyboard and out eating so.

Make sure you get a hat ticket for your ego as I know you'll need it for use later unfortunately.

[UrS4boy]

C4 HVAC Stepper Motors

The air into the passenger compartment is pushed in by the heater fan (blower). The temperature of the air and the direction the air is pushed is controlled by three stepper motors that the Climate Control Head uses to open or close or partially open or close three main flaps.



As far as I know, there are three stepper motors connected to (literally) the C4 UrS (and 100/A6) HVAC heater box. These are:

1. V68 - Temperature regulating flap motor. Left side of the heater box, in the cowl area, white mechanism arms. This, along with the signal from the G92 temperature flap position potentiometer, allows the Climate Control (CC) head unit to control the position of the large flap between the heater blower and the heater core.

Sometimes the arm between the flap and the V68 stepper motor comes off. This can be remedied by following this temp flap stepper motor Re and Re DIY by Steve Y. of New York State, USA (long time UrS owner and writer of several excellent UrS DIYs): Click Here

2. V70 - Central Flap motor with G112 position potentiometer, aka "fresh air flap". On the right side of the Heater Box, inside the passenger compartment. Blue electrical connector and blue mechanism arms. No heat out of the central dash air vents? This is likely your problem. Stuck or failed motor or bad signal. See links to diagnostics under the two annotated photos

3. V85 - Footwell/Defroster Flap Motor with G114 position Potentiometer. On the left side of the Heater Box in the passenger compartment. Red electrical connector and red mechanism arms.





REFERENCE:



HVAC Control Head Diagnostics:

Live version: http://www.audiworld.com/tech/int5.shtml

Same info but as a pdf suitable for printing off and taking out to the car: http://12v.org/urs/Climate%20Control...0&%20Codes.pdf



Hope that helps.

[UrS4boy]

Forgot one: V71 back pressure flap motor (UrS6 only)

V71 Stepper Motor - C4 A6/UrS6 Back Pressure Flap Motor

This was on my 98 C4 avant but is not present on my 93 UrS4. Skollie had it nailed in this post

Control motor V71 (4A0820511A) Air flow flap (on left in plenum on climate control):

1. This is the easiest of all 4 air actuators: First remove the front cover (rain tray) of the water box (cowl) under the hood, it is only clipped in 4 places.



2. There is the flap motor, under the black cover with the red tag, to the left (in the photo) of the blower box.



3. To access the motor, remove the two cover screws and lift off the cover:



4. Careful that the Torx screws do not fall into the housing, remove it and set it aside. Lift the lid gently, let the gears and shafts in lower case.



5. Carefully pry the motor up, he's just snapped and remember position before disconnecting the connectors. Operate the engine at the laboratory power supply with 7 volts DC, he should have about 25 mA current consumption, if not then clean with a needle the joint between the three collector parts of carbon and copper deposits. Potentiometer to spray some contact spray from the wire side and with compressed air to blow again, less spray is better than too much. Then reassemble. Since no flap setting was changed, a "breaking in" the door is not necessary.

[Harvester]

Thank you very very much for your answer

And the ducts are iluminated , or not ?

[UrS4boy]

Thank you very very much for your answer
And the ducts are iluminated , or not ?

No illumination from the factory. Some people might have added them, along with wheel well lights and running board lights, a three level rear wing and fuzzy dice.

[Harvester]

Okay , I though that c4 has iluminated ducts like b5 a4 and c5 a6 I had a V8 time ago and it has iluminated ducts But I m not sure .
Thank you for perfect answer anyway .

[UrS4boy]

HVAC System Stepper Motor Replacement/Repair

..Thank you for perfect answer anyway .

In case you need it, here is a translation of a German-language stepper motor replacement/repair DIY that I did yesterday:

http://forums.quattroworld.com/s4s6/msgs/299258.phtml

[Harvester]

Will you marry me ?

[UrS4boy]

Will you marry me ?

Umm.... Sorry, you're not my type and I'm too old for you.

I was meaning to do that translation and document the stepper motors for a long time. Your issue just brought it to the top of the list.

[Harvester]

Thany you very much As soon as it stop raining or what is it doing it here right now I am on it .