Does this happen when car is cold ?

The only control for high speed operation of aux fans seem to come from CCU. The only control for low speed operation of aux fans seem to come from the freon high pressure cut-off switch. So if the CCU is set for no a/c operation and the car is cold, you should not have aux fans come on at any speed. If it comes on at high speed when the switch is on run position, since you have already replaced the CCU, I would think that your coolant temp sensor is signalling a wrong signal, a signal that is equivalent to car being hot. BUT I have no idea why the temp sensor signal is suddenly being interpreted differently once the car starts, strange.

If the fans come on at low speed when the car just started from cold, that means there is a very high freon pressure sensed by the pressure sensor. If the a/c has not been turned on for this test, there is no reason for the pressure to be high, so I would think that your pressure switch is bad.

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Saumil S. Patel