07 Chevy Cobalt lights

my sister has a 2007 cobalt and for some reason all of a sudden her headlights will not turn off unless she disconects from the battery!!
Any Ideas on what it may be? Thank you

The body control module (BCM) controls all these functions. Usually disconnecting the battery and 'rebooting' it is a cure. Did anything lead up to this? Aftermarket electronic installs? Trying to jump another vehicle? Typically these things don't go bad on their own.

Joel