What do the brush-roll indicator lights mean on my Shark Duo vacuum?

A solid green light means the brush-rolls are spinning and working properly. A solid red light indicates a jam in the brush-roll area—turn off and unplug the vacuum, then remove blockages. A flashing red light means the motorized floor nozzle is overheating—turn off the vacuum, unplug it, clear blockages, and let it cool for at least 60 minutes before restarting.