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Cooling Fans do not shut-off with A/C on

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I am trying to fix a problem with my 05 Cayenne S.  If I do not shut off the A/C before turning off the car it tends to run until the battery drains.  I am short on time and brought to a general wrench who needs resistance values to test the fan motor - I would appreciate if anyone has them.  Also, any suggestions on whether this is consistent with a fan, DME, blower mower or temperature sensor issue are greatly appreciated - I have read a number of threads but there is not a consistent solution.  FYI - the temperature gauge shows normal temperature and I have started experiencing groaning with the a/c blower after driving for 10 mins or so.  I do not have a code but might take the car back to run a durametric scan if that will diagnose the issue.  Many thanks in advance for your replies.

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Your Cayenne, like most late model Porsches use solid state pulse width modulation rather than resistance to control the engine cooling fans.  It uses a signal from the DME to not only turn the fan on, but also control the fan speeds. This system is built into the fan motors and is not serviceable.  It is entirely possible that the solid state controller has failed, which means the entire fan has to be replaced.

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Many thanks!   Will there be a code that the durametric will show me to confirm the controller is faulty and not another cause?

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