Strange occurance with my climate control

[SynisterQ]

I started up my car after work yesterday and turned on the AC for about a minute then realized, wow, it feels so nice out, I'll just roll down the windows. But as I turn off the AC, the display is blank but the defrost and the feet vent is blowing really hard. So I turn the AC back on and it works like it should. Well, I drive home with the AC turned off but the defrost and feet is still blowing. Should I just clean the connections on the back of the AC control or is it the Darlington (?) resistor that needs replacing? Maybe it'll clear up in the morning, because this has never happened before.