HDD Bay 3 and Bay 4 not detecting new hard drive

[DanAlexander]

Hello people!

I have a HP z820 workstation with 2 hard drives: a primary SSD as boot drive and a secondary internal HDD.
I want to add a new drive, but Bios and Windows doesn't see it. 

When a take out my internal HDD and replace with the new one, Bios and Windows see it normally - and because of this I've formatted it with the hope that Bay 3 & 4 will recognize it.

It seems to be a problem with Bay 3 and Bay 4. They are not activated or what? Where can I find some info's. I've searched all the internet for some information and nothing.

Thanks,

[Brian1965]

Please confirm there are 5 cables as I've indicated in the image below;

Please also confirm that the SATA ports are active in the BIOS - Security > Device Security

Here's a better image I found;

Please note that the DVD SATA cable is NOT shown in the above image, (only the SSD/HDD SATA cables).