I'm pretty new to my 2006 XC90, but a strange thing happened today. So far, every time I turn off the engine and remove the key, the interior A/C blower fan also turns off as expected. Today, the interior A/C fan continued running even after removing the key.

I inserted the key, started it again...turned it back off and the fan turned off as expected.

Is there some reason this would have happened as designed, or do you think I may need to replace the ignition switch soon?