Here's what I did for the plastic guides that broke as the slideout ... I got the idea from the MOC membership. No problems since.
I used 4 1/2" hinges fastened to the metal slideout and the other side attached to the plastic guide. The toughest thing to do was drilling the holes in the metal. I used machine screws and nuts to fasten it all together. I did this on three slides in my rig. If you need more details, PM me.
I don't understand your question about getting the wires through the holes? Does my picture show what you are really asking about?