The SAS Activity LED is located at LED1 on the add-on card. When LED1 is blinking, the SAS connections supported by the Avago 3108 controller are active. See the table below for more information:

SAS Fault LED
LED6 is used to indicate if a SAS failure has occurred. When LED6 is on, an error has occurred to on-card SAS connections. See the table below for more information.

System Heartbeat
LED The System Heartbeat LED is located at D13 on the add-on card. When D13 is blinking, the system is functioning normally. See the table below for more information.

You can find more information about the RAID card in the following link:
http://www.supermicro.com/manuals/other/AOC-S3108L-H8iR.pdf
If none of the LED are working, please try to reinsert the RAID card and restart this device. Please be sure the NR9X81 have been turned OFF before trying to reinsert the card. If after reinserting the RAID card many times, the device still cannot detect the RAID card. Please ship this device for RMA service.