Is it possible that you have a different sensor/switch arrangement in your car ? Someone familiar with this car can pitch in here. Or could it have been a coincidence that the fan came on when you pulled the cables out. Note that atleast in my 87, 260E, the fan can come on from different sources. One is the engine getting too hot (this is the coolant temp sensor), and this always turns the aux fan on at high speed (the current for the fan comes from aux fan relay in the relay box) AND another by the climate control unit, if the settings are for highest a/c and highest blower speed, this also turns the aux fan on at high speed (the same relay supplies the fan current) AND the other is if the refrigerant presure becomes too high, and this is the pressure switch (most likely on your drier), this turns the aux fan on at low speed (a different relay in the box handles this circuit).

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Saumil S. Patel