A8 / S8 (D2 Platform) Discussion Discussion forum for the D2 Audi A8 and S8 produced from 1994-2002

Air Velocity

 
Old 04-30-2019, 07:06 AM
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Airflow coming out of heat/ac system is about 25% of normal. Confirm fan is properly working at 100%. Does not matter what mode - heat - cool - fresh - recirculate - foot vents - back seat vents - defrost - face vents - temp. It's as if the entire system is either blocked or there is a hole that is venting air.

The flap setup is quite complex but given that it seems to affect ALL modes AND the fan is fine would seem to indicate an issue early in the airflow process.

Any ideas out there? Thank you
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Old 04-30-2019, 08:17 AM
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What sort of car?
If the blower motor was replaced some of the replacements are wired backwards, which causes something like what you describe. If it's a D2 check the HVAC filters.
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Old 04-30-2019, 08:49 AM
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1998 A8 D2 . 4.2 Quatro
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Old 04-30-2019, 08:52 AM
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Thank you - I will check those items. If it was the polarity on the fan motor wouldn't the ducts not blow ANY air but actually draw backwards? My ducts all blow air - just at a much reduced velocity
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Old 04-30-2019, 09:34 AM
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Did it ever work OK for you? And then did the motor get replaced?

Reports in the D2 forums suggest people feel some airflow at the ducts when a backwards blower motor is installed. I am not sure why, maybe a backscatter effect.
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Old 04-30-2019, 10:32 AM
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has never worked for me and any work was prior. I'll dig in today and see what I can find. Thanks for the help - I'll let you know what I find out.
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Old 04-30-2019, 07:39 PM
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pay attention to the wires on the pigtail for the motor, if it's wired backwards it will be obvious. you will see red going to brown as I recall.
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Old 05-01-2019, 01:26 PM
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That did the trick! Thanks Audinutt. Once I unpacked the cloth tape on the blower loom I could clearly see that the actual connector was wired incorrectly. Brown going into Red. Flipped the polarity and the air velocity tripled at least.

If you're ever in the Pacific NW of the US I owe you a beer.
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Old 05-02-2019, 06:34 AM
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Thanks for reporting back, always nice to see something resolved. -Joel.
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Old 05-02-2019, 08:54 PM
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This issue nearly drove me insane... in fact I sold a car dirt cheap due to this issue AFTER changing the blower.. I swapped flap motors, etc, etc thinking something else was wrong. I gave up and sold it for one heck of a bargain.
Then I bought another d2, and the blower started to fail. I bought a replacement and as soon as I installed it I had the SAME issue again... then I looked further and discovered the pigtail was wired backwards!
I called the person I sold the car and fixed it for him too.

This is clearly a widespread issue with the blowers (a batch was made incorrectly).

Glad I was able to help you though!

-Richard
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