this stupid fan has gone off in my car when driving from the driveway into the garage in the middle of winter when the temperature was under 50 degrees Fahrenheit. It can stay on for days until I unplug it. Of course the dealer can never replicate the problem. I have gotten very use to unpluging it when it stays on for greater than 15 minutes after turning the engine off.
The bad news is, is that when you plug it back in, even when it has not been started for days, it will still go back on... some sensor problem. If I drive it far enough that it legitimately heats up, then it will turn itself off upon stopping the engine.