You could try to turn on/off System FRU LEDs from service processor
- Enter Diag mode:
SP filer> priv set diag
SP filer*> system fru list
SP filer*> system fru led show
SP filer*> system fru led set <number> on
If that doesn't work get the serial number of PSU from Service processor
1. SP filer*> system fru log show
The serial number is located in the rear side of the PSU (match the serial number)
hope it helps