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Fan Noise/Pump Passenger Dash with ignition turned On

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Good Evening,


I am new to the Porsche world and recently purchased a 1999 Guards Red C2.  In the past few days I have noticed a loud fan noise/pump noise under the passenger side dash when the ignition key is turned to the on position.  This noise seems to be independent of the AC fan.  I am not sure if this sound is normal for a 911 or something that I should be more concerned with.  I will note that the noise will continue until the ignition is **** off.  With that being said, I was wondering if anyone knew what this noise could be and if it’s something I should be more concerned with. 

Thank you in advance for your help!


P.S.  I did take a video of this noise and can post it once I figure out how to do so.

Edited by Yellowlimited93
Added Video

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The only fan under the dash on the passenger side is the HVAC system fan.  Does the noise change when you increase/decrease the fan speed?  Have you checked the cabin air filter for debris?  The HVAC system fan is always on with ignition on unless you hold the decrease fan speed button until it shuts off.  The next time you start up again the fan will be on again.

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The noise you hear is with the HVAC fan manually turned off.  The noise does not change with fan speed as I can separately hear the HVAC fan running.


I have not checked the Cabin Filter (I did purchase a new one) but I am unsure why the noise is present when the hvac system is off.


Thank you for your help.

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