Can you see Wifi in the Settings or is it grayed out?
I bought a replacement wifi cable thinking it may solve my decreased signal strength. But I am disappointed to find that one side of the cable appears to be attached directly to the circuit board and there is no connector.
Maybe someone else knows how it is connected but to me it looks like it was done with a very expensive machine that has to place it exactly in one location to make all the very small tabs line up.
There is a small ribbon cable section that goes off parallel to the main cable that connects to the volume control but I don't think this slide connector being loose would impact the wifi.
There is also a small cable that does not come with the replacement wifi cable and is seen in step 10 of the tear down and the letters CE are just below the ribbon. I have no idea how this small ribbon is attached to the wifi cable.
If you have very limited connectivity it may be that the ribbon cable has pulled loose from the back of the iPod case.
In step 10 of the tear down you can see three tan colored rectangle sections with radiused corners. They are covered with what I will call "conductive glue". Underneath this "conductive glue" are copper pads. I believe these pads need to contact the metal case back for proper grounding. The "conductive glue" allows a electrical path to the ground plane. On yours this may have pulled loose.
I am calling it "conductive glue" in quotes because I do not know the proper name or where to buy it.