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[wernerc]

Hello,

I own a Think from 2010 with Zebra battery which has a problem with the radiator fan control.
2-3 seconds after turning the ignition on the fans start with full power and noise until ignition is turned off again. Driving in this state is not really charming as its very loud and the fans may be worn very quickly.
What I did up to now was the following diagnostics:

I examined the relay control for low and high fan power stage by separating the control wire from the relays and control it manually with a wire.
Both relays work like intended and both stages can be controlled, no problem with the resistor on the fans for example.
I can recognize that the relay for the high stage is controlled shortly 2-3 seconds after turning on the ignition with no load on the car or charging or whatever, so any real overheating can be excluded from my point of view.
Reading some CAN values from the PCU the ambient PCU temp was 8.5C which is not in the range that a fan should start. No errors seem to be reported by the car itself.
All other functions of the car work like desired.
I assume that the fans are controlled by the PCU ?? but I have no schematics so that I can approve this.
I thought about the fan relay driver inside the PCU to be defective, but it needs 2-3 seconds (like a short delay for a self test or whatever) until the relay is turned on, so I disregarded this thought again.
Does anyone have had such a problem, too ?
And can anyone give any helpfull information, schematics, diagnostics or even CAN messages to decode or send for checking the fan control ?
Is there any diagnostics software available for the PCU ?
I know Zebramonitor, but this allows access to the BMI only and does nothing with the fans I expect.
I also checked GEM conections if the fans should be controlled by this module (switched via CAN msg from PCU for example), but the GEM is not involved, it seems that the relays are directly controlled by the PCU.

It would be very nice if someone could help me with this problem, even if the solution or diagnostics seems to need complicated things like sending manual can messages or similar.
I am an engineer with much knowledge about automotive products, but without the appropriate documentation (schematics, CAN codings) or alternatively simple diagnostics software such problems are tricky.
And I don't want to remove and disassemble the PCU for checking any drivers or whatever if its not needed and I don't expect a driver problem there.
I read that there is some software for PCU diagnostics existing ??
Where can it be retrieved and which adapter is needed then (CAN or special) ??

Thank you very much for any answer.
I am speaking english, german and some french only, so any norwegian or swedish messages can only ne translated by google or whatever here.

Werner