ESX: Find logs to prove Fibre card is faulty

Background info :
Started with VMWARE reporting Dead LUN Paths on a VMHost
The Dead LUN paths has been cleared since then

Onsite tech reckons the Fibre switch port is working fine and the fibre cable is fine.


Now focussing on the ESX box itself
To track down the Hardware Fibre card that might be faulty, that we can prove where the fault lies

requirement
1. Looking for guidance on where I can find logs or errors in Vmware or anywhere else on the Linux os to prove the adapter is faulty  
1.1 I need to find which adapter is faulty
1.2 any errors that can prove it

thanks