2002 S60 AWD ECU fan won't switch off

[emd886]

Hi! Normally, after switching the engine off, the ECU fan would come on when it's hot, runs for a few minutes, then shutoff. However, lately, it's been coming on but not shutting off even after 20 minutes. The ECU and TCU modules inside are warm, but not hot to the touch. So what i'd do is turn the ignition key to position II, then turn off again; that process would shut down the ECU fan.

1. I'm assuming there's a sensor somewhere that controls the on/off power; where is it?
1. Does the ECU fan have it's own relay, or what relay does it use, if any?
2. if it's the ECU fan, does it have anything internal that could cause the power to not cut-off?
2. Any other thoughts?

Need some help pls. Thanks.

[oragex]

20 min doesn't look that excessive to me, does it shut off after 20 min? Mine too is hissing for quite a while because the engine will keep hot so the engine bay it's still hot for a while