Audi A4 (1995 - 2000) - 95 2.6 Heater Fan running without Climate Control

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Thu 20 Aug 2009 17:54
95 2.6 Heater Fan running without Climate Control - autumnboy
I've been trying to solve my heater fan blower problem, where it runs at top speed no matter whether or not the LCD Climate Controller is connected. When the controller is fitted, you see the scale showing the speed adjustment fast or slow but the actual fan speed remains the same.

I've tried another controller without any difference.

Its weird where the motor runs at full whack even without the controller being fitted.

Any Clues

Thanks
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Thu 20 Aug 2009 18:02
95 2.6 Heater Fan running without Climate Control - AndyT
I can only suggest that there is a speed control wire between the controller and motor, which is not making contact. I don't know the set-up, but there's maybe a positive and negative supply to the motor, with a third speed wire also.
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Thu 20 Aug 2009 18:32
95 2.6 Heater Fan running without Climate Control - autumnboy
Thanks,

But no, only two wires to the motor.


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Thu 20 Aug 2009 18:46
95 2.6 Heater Fan running without Climate Control - Peter D
This car has a Fresh air blower control unit J126, If this has failed then the fan does run flat out no matter what you do unless you pull S225, but then a lot of stuff goes off. I would have to seach a lot to locate the device but a code read should identify if this is the problem. Email me if you want the diagrams at Info@3DAssociates. co .uk ( remove the spaces, anti phishing) Regards Peter
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Thu 20 Aug 2009 18:52
95 2.6 Heater Fan running without Climate Control - autumnboy
Thanks,

Done a Vag test, but this only shows faults (sensors) other than the blower module. I've a drawing from an other Website which the PDF is from Audi of America for Climate Circuit.

But finding this J126/module is the problem.

thanks again

Edited by autumnboy on 20/08/2009 at 18:54

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Thu 20 Aug 2009 18:56
95 2.6 Heater Fan running without Climate Control - Peter D
It is exposed by removing the glove box and yes you are right a shorted J126 does not show up on any diags. You have to remove the glove box and the glove box holder. Regards Peter
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Thu 20 Aug 2009 19:33
95 2.6 Heater Fan running without Climate Control - autumnboy
Thanks again,

I've already got the glove box out and can see where the flap control is etc and the wiring loom etc. But what am I looking for, whats the J126/control module look like to Identify it.

thanks
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Thu 20 Aug 2009 19:35
95 2.6 Heater Fan running without Climate Control - Peter D
So email me. Regards Peter
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Thu 20 Aug 2009 19:36
95 2.6 Heater Fan running without Climate Control - elekie&a/c doctor
The electronic fan speed controller is mounted in the air ducting behind the glovebox.It is an aluminium heat sink device that usually has a red plastic cover.hth
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Thu 20 Aug 2009 21:10
95 2.6 Heater Fan running without Climate Control - autumnboy
Thanks Guys found it.

Next question, any way of testing it to find if faulty.???

thanks
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Thu 20 Aug 2009 21:18
95 2.6 Heater Fan running without Climate Control - Peter D
Use a meter set to a low ohms range between pins 2 and 3/31 if these are a short in either direction then that is your problem. Regards Peter
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Thu 20 Aug 2009 21:35
95 2.6 Heater Fan running without Climate Control - autumnboy
Peter

You are right, pins 2 to 3 shows a short circuit.

I've been searching and been to various Audi Forums UK and USA for some 2 weeks asking for this.

Then ask the same question here and its all sorted within a couple of hours.

Thanks again Peter for your help.

Pity we don't have a 'thanks' link.
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Thu 20 Aug 2009 21:42
95 2.6 Heater Fan running without Climate Control - Peter D
You are welcome. Use www.vwAudiforum.co.uk and you would attract a quicker response. Regards Peter
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Thu 20 Aug 2009 22:21
95 2.6 Heater Fan running without Climate Control - autumnboy
Thanks Peter,

User/Member, I've been there in the A4 B5 section with no joy, also to audiforums.com

Tel
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Thu 20 Aug 2009 23:18
95 2.6 Heater Fan running without Climate Control - Peter D
I've been away in the US for 5 weeks on vacation so missed your request. All is well that ends well. Regards Peter
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Fri 21 Aug 2009 08:42
95 2.6 Heater Fan running without Climate Control - Collos25
Diodes gone on the fan motor common fault.
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Fri 21 Aug 2009 11:29
95 2.6 Heater Fan running without Climate Control - Peter D
J126 is a mosfet current control regulator there is no diode in the motor. As there is a short across the input and output pins in either direction the Mosfet has failed short circuit thus the motor only runs at full speed. Regards Peter
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