What to do if your dome light will not turn off in Impala/2010?

There should be a dome over ride button located on light stalk (turn signal) or dimmer knob on dash. Rotate away from click point close doors wait 1-3 mins light should time out unless there is a door open or latch not showing all zones (door) closed.

At least one of your door switches is stuck closed and causing the dome light to remain on. The switches are either plungers in the door jamb or switches in the door latches. A plunger can easily be lubed or fixed. A switch in the door itself is more difficult to fix. To free up a stuck switch or plunger, access the area enough to get a spray contact cleaner or WD40 to it. That is often all it needs. If this doesn't work, you're looking at a replacement.