HOME...ToreB is the undoubted expert here, of course my simplistic thinking had not known until now of a car HEATER circuit being designed to also to cool an engine, though have done that myself in my old and very basic sports car when it was running HOT while driving in Italy..... We were both over heated and my dear lady wife was not too happy when I prioritised adding heat to the passenger compartment in a bid to achieve a measure of engine temperature reduction..!!!
Ever in search of simplification..... It seems "climate control" is the way of it these days involving a ever more complex aspects of heating and cooling systems for the cabin, aspects of which have seemingly been PROGRAMMED to perform engine cooling after shut down...?
Not knowing the construction of the circuit, I imagine there will be a sensor which ToreB identifies as the "thermoswitch" it will probably be this device that controls whether the fan is switched on or not.... with a resistor in circuit, logic seems to suggest that the speed of the fan is desired to be controlled for cabin heating AND/OR engine cooling... are we talking the same fan...? If so, I guess there may also be auto control of flaps to divert the airflow from cabin to the car exterior when in engine cooling mode...?
The thermoswitch may be other than an off on switching device for the fan, and may have the capability to also control the fan speed, the thermoswitch having internal contacts that can switch in or out sections of the resistor dependant on temperature, and in so doing raise or drop the current available for the fan... which affects it`s speed..
While ToreB determines there is no way a problem with the resistor can create an abnormal current drain in this case, I would not be confident enough to make such a statement having discovered burned out resistors causing shorts and higher than expected current drains... BUT I have ZERO experience in Porsche terms in this regard thus would automatically give ToreB`s statement the credibility it deserves..
If there is indeed no way that the resistor could cause your discharge problem, then the thermoswitch becomes the next in line suspect HOWEVER if there are any relays in the circuit they too can hold the fan ON even after the thermoswitch has operated properly disconnecting the supply to the relay(s).... How you might ask..? Well the contacts in the relays can burn over time after many switching operations... The effect can then be to create an INTERMITTENT fault...as the relay contacts can stick on or not after each switching operation, the cause of which can be a real pain to determine... more so when relays these days can not be opened and contacts cleaned... Thus this where replacement takes over from attempts at repair.... Replacing the relay might be cheaper than the thermoswitch, though I might expect a garage to replace both rather than have the customer have to come back when the same fault occurred... Of course if the thermoswitch requires an engine out or any such nonsense, then economics is ever bound to play a part in such decision making... :?:
Making any sense.. :?:
More than happy to be corrected on any and all that I type, I come here to learn.
ToreB, if you read this far... Yours is a CRACKING web site... THANKS.