ECU cooling fan operation

[darrylrobert]

Neither of my 2001 or 2002 xc70's have the little ECU fan, keeping such an important computer cool especially in a hot climate like Australia. Im thinking maybe the hot weather issues i am having maybe due to the ECU overheating?..i checked the temp of it after a drive (25c day) and it was very hot to touch.

My old 2001 ECU box has the (pic right) old ventilation port that would go to the fan shroud however this port is blocked, i was thinking of drilling small holes and attaching a hose on it but that my be sending hot air from the engine bay past the ECU and into the cabin? bad idea ...so instead i updated the box from my 2002 which can take the ECU motor.

whether the ECU motor sucks air or blows air i will find out when it arrives but in the meantime i want to check it runs on a simple 12v input and not some pulsed modulated signal?

[oragex]

The small fan on cars after 2002 or so works usually well enough, on hot days mine keeps spinning after turning off the engine, for some 2-3 more minutes. As it gets old, it starts making a hissing noise that can be heard from inside the cabin. The modules do get quite hot to the touch - even home computers can take some heat

[Jarredron]

Does the fan spinning for minutes after turning off engine stress the battery at all?

[oragex]

Oh, absolutely not. It's a small DC motor that uses no power, can even be powered by a small 9v battery.
Speaking of the ECM box with an opening for early models, I also noticed that at the junkyard. I thought first it had a tube at the front grid for fresh air, then I realized that would also get humidity from rain at the ECM modules - not good. I always double check the bottom section of the ECM box because it doesn't always stay properly and leaves a gap - that can accumulate humidity when rain passes through the radiator and the large connectors at the bottom of the ECM are quite sensitive.