I removed the backplane and replaced it with another from a spare machine and I've got green lights across the array!   I'll pop the original backplane into another machine to see if I can reproduce the issue.   All good as of now!  Thanks you guys for the support, always a learning moment 
I inherited an r415 that I use in my home lab.  I has a PERC 700H and 4 bays.   All firmware and drivers are updated to the latest versions available as of this post.   Drive Bay 2 shows intermittent issues in the system log as it goes between "Drive Fault", "Drive Removed", then "Drive Installed" and behaving normally.  The drives are configured as RAID 5.   I have successfully rebuilt the allegedly faulty drive and it seemed to complete, but the caddy still flashes orange or, right now, with no light on at all. To test the machine, I swapped out all 4 drives with new SATA drives and again set them up as RAID 5.  Same issue occurs. My question is whether this might be a drive backplane or SATA/SAS connector issue? Is there anyway I could check this?
Powered R415 Backplane Issue?