If you plug in the Porsche part number to an Interchange parts list - what comes up?
Part number is :996.616.101.00
This link may help?
Step by step DIY with pics radiator ballast resistor replacement - Rennlist Discussion Forums
http://www.renntech.org/forums/topic/37254-radiator-fan-question/
There is a Hack -buried in this thread:
http://www.renntech.org/forums/topic/20479-radiator-cooling-fan-question-yup-i-searched/
Just google Porsche hack Ballast Resistor fan cooling radiator or similar.