You can replace fan modules as needed while the switch is operating ("hot swapping").
All installed fan modules must blow air in the same direction and must match the airflow direction of the installed power supplies.
If the switch's fan tray has a red tab, the airflow is front-to-back. Use a fan module labeled Air Out.
Note
The operating-system software cannot display the airflow direction.
Before you begin, have the replacement fan module on hand so that you can complete the replacement promptly. The switch can overheat if left without adequate cooling for an extended time.
To replace the fan module in a switch, do the following.
The fan module is held in place by spring clips. As you pull, the clips will disenagage and the fan will stop.
Fans with front-to-back airflow have red tabs and are labeled Air Out.
Push until the fan module snaps into place. The fan will automatically start to operate.