Laptop doesn't detact HDD W10JPCX at SATA port of the optical drive

Hi there!

I bought a new laptop (Lenovo Z51-70). In there was a WD10JPCX HDD. To fasten up the laptop I bought a SSD and a caddy to adapt it in the SATA-Slot of the optical drive. Unfortunately that didn’t work, because of UEFI and Win 8.1. I wasn’t able to boot from the SSD. So I switched places between the SSD and the HDD. The SSD is now in the system and runs properly with Win 8.1. Now I insert the WD HDD into the caddy, because I need it as additional storage space. The HDD is formatted like it was when I took it out of the laptop. So there is still Win 8.1 installed on it. When I now turn on the laptop it boots from the SSD (like I want it). The HDD starts running and the light is blinking, but a few seconds later it stops. This tells me, that the SATA-port where the HDD is linked on, is kind of working. But in the system I can’t find the HDD. Neither in the device manager, nor in the disk management. I tried even diskpart, which also doesn’t show me the HDD.
What can I do? What is the problem?
When I bought the laptop the HDD was the only disk in there, so possibly it is kind of “jumpered as master” (don’t know if that is done in laptops, I just know it from former times as teenagers when I used to work with desktop PCs) and it needs to be slave now? Or is it due to the energy supply?
Can someone please help me or give me a hint!?

It’s likely a power issue since SATA drives don’t use a master/slave configuration.