hope someone can help as I know nothing about this.

Basically I removed my head unit to replace it (I actually couldnt get this working due to a completely different issue)

So I have went to put my old headunit it and noticed a couple of wires soldered onto some other wires, but Im not sure if they fell off when I took out radio or what they were doing.

I put the headunit on, and now it only powers on for a few moments, then it just goes off, non of the buttons work either, so it just seems to turn itself off, it doesnt last very long.

I have read this may be a grounding issue? Ive never heard of having to do any grounding? Attached are the pictures of where a wire was, it was almost like it was another piece of wire joining these two together? Should I get some wire and join them? Or how do I "ground" it?

Hope someone can help, very stuck with this!

(black wire, and yellow wire)

If you have the correct multi pin adaptor for you
vehicle, it will be grounded through the wiring harness.
The black wire is the Earth.
You do not have to make any additional Earth or Ground
connections.
Hope this helps.

Ok so basically there is no additional earthing, I think the headunit must be broken since I took it out. Ill get another one and see if that works, hope it does!

Cheers!