External GPU for Macbook Troubleshooting

[Mitro]

So I decided to build an external GPU for my macbook pro 2015. I used a setup recommended by a website called egbukitproject.com which shut down shortly after I ordered all the components. I Spent about ~£450 on the products below:
- Zotac GTX970
- Akito Thunder 2 PCIe adapter
- EVGA 500W psu
- Thunder 2 cable
- PCIe 16X Male to 16X Female Extension

I installed the latest version of Windows 10 using boot camp assistant but when I used the relevant driver software, it doesn't register that there's a gpu connected. No fans spin on the psu or gpu, no lights come on - basically there's nothing to suggest that they're even turning on. I was told by a friend that the psu might not start without a kick from the motherboard; either that or it's broken entirely (although i bought it new so that's unlikely).

Skip to 16:10 in this video - that's pretty much exactly what I did.
https://www.youtube.com/watch?v=LePHJ2rG05c

Any help/suggestions are welcome! Thanks!

 

[Mitro]

How exactly are you starting the PSU if I may ask? You should try shorting the PSU like so: http://www.instructables.com/id/How-to-power-up-an-ATX-Power-Supply-without-a-PC/

I hadn't thought that was an issue until now, a friend recommended trying to use a psu tester which just arrived. i'll try that then the link you sent me, thanks!

 

[Mitro]

Well as the 24-pin isn't connected to anything the PSU won't turn on when the laptop does, so your GPU isn't getting any power. A simple button for shorting it out would be best, but you can use the switch on the back as well (as long as the green and black wires are shorted that is).

can you recommend somewhere to buy a switch as in the instruction you linked me? Switches are easy enough to find but none come wired which isn't ideal.