Vent/Air on 1994 Buick Roadmaster

Why does vent keep running when I turn power off and turn car off?

There could be a couple reasons for the blower fan to keep running. Ideally you'll want a wiring diagram and a voltmeter to diagnose this problem to determine what is wrong. Or take it to a shop and have them diagnose it for you.
Yea, I figured as much, thanks.