Troubleshooting the Power Supply Fan

To check the status of the power supply fans, perform the following procedures:

• Check LEDs. Two LEDs on the power supply faceplate report the supply's status, including the status of the fan. If the amber LED labeled FAULT is lit, the power supply fan might have failed. For more information, see Power Supply LEDs. Power supply failure also triggers the red alarm LED on the craft interface. For more information about alarm LEDs, see Alarm Relay Contacts, LEDs, and Cutoff Button
• Issue the following CLI command to check the status of the power supplies. As shown in the sample output, the value OK in the Status column indicates that the power supply is operating normally, implying that its internal fan is maintaining an acceptable temperature:
  user@host> show chassis environment

  Class Item                   Status     Measurement Power Power Supply A         OK                    Power Supply B         OK ...  

  For further description of the output from the command, see the JUNOS System Basics and Services Command Reference.