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Author Topic: Why is my fan on all the time when air con is on?  (Read 1791 times)

Offline njdudsbury

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Why is my fan on all the time when air con is on?
« on: September 15, 2010, 10:42:54 pm »
Hi all
Over the last few months I have noticed that my fan comes on regularly when i'm driving. (short journeys)
The temp gauge always seems ok and no differnece in performance and the fan then goes off in a short while.
When I put the air con on the fan seems to come on almost instantly and stays on until I turn the aircon off. (I tried it the other day and left it on for approx ten mins and the fan stayed on all that time, as soon as I turned the air con off the fan turned off a few seconds after)
Is this normal or is it a fault?
Anybody else had similar?
Cheers

Offline bacillus

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Re: Why is my fan on all the time when air con is on?
« Reply #1 on: September 15, 2010, 10:46:30 pm »
Normal behaviour.   :smiley:
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Offline Weston

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Re: Why is my fan on all the time when air con is on?
« Reply #2 on: September 15, 2010, 11:10:48 pm »
Mine does this all the time. One garage tried to charge me almost £500 to replace both fans, then another place said it was perfectly normal  :laugh: It's really loud but I don't think there's anything wrong with it
GTI going...

Offline bowie

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Re: Why is my fan on all the time when air con is on?
« Reply #3 on: September 15, 2010, 11:41:45 pm »
Its not just an engine cooling fan. I believe theyre called an auxillary cooling fan and they assist the air con .

Chris.
2010 Golf R DSG. Reflex. 3dr.

Offline dajonic

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Re: Why is my fan on all the time when air con is on?
« Reply #4 on: September 16, 2010, 09:23:50 am »
Yep think it's just the way it works for the system. My aircons on all the time and so are the fans. I can't hear them though until I get out of thecar and they quickly shut down after the cras turned off.

Offline RENNTAG

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Re: Why is my fan on all the time when air con is on?
« Reply #5 on: September 16, 2010, 09:30:55 am »
This is normal.
the condensor for the aircon is mounted up the front with the radiator, this is were it gets rid of the heat from inside the car so it can cool you down.
the fan needs to run to keep air passing over the condensor to remove the heat.
hope that makes sense  :smiley:
« Last Edit: September 16, 2010, 09:53:43 am by bendy »

Offline Richn83

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Re: Why is my fan on all the time when air con is on?
« Reply #6 on: September 16, 2010, 10:26:57 am »
This is normal.
the condensor for the aircon is mounted up the front with the radiator, this is were it gets rid of the heat from inside the car so it can cool you down.
the fan needs to run to keep air passing over the condensor to remove the heat.
hope that makes sense  :smiley:

Nicely put Bendy!  :drinking:

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Offline DooDah

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Re: Why is my fan on all the time when air con is on?
« Reply #7 on: September 17, 2010, 08:33:53 am »
This is the same as the Mark 4s fitted with the climatronic system. The fans are two speed and like the earlier comments say the slow speed fans operate continuously when using the air con to cool the air con compressor down. The fans on the mark 4s were and are notorious for having the slow speed resistors failing in the fans. Have not heard the same problems with the Mark 5 though.

Offline ub7rm

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Re: Why is my fan on all the time when air con is on?
« Reply #8 on: September 17, 2010, 09:40:42 am »
^^ Same thing happens with the mk5, small fan fails and the big fan kicks in all the time.  If you can hear it in the car it probably means the small fan is goosed.
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Offline neg

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Re: Why is my fan on all the time when air con is on?
« Reply #9 on: September 19, 2010, 04:38:01 pm »
Its a common fault on lots of cares - Mk4 and mk5 Golfs, Rovers, MINI's to name a few.  Expensive to repair properly but on some you can get a 'fix' to just replace the resistor and that solves it.

I did the NIME fix on the mk4 we had - worked a treat.