Start shaking wires also, try pulling your fuse , Clean the fuse prongs
Once upon a time , buddy of mine , went to the pick n pull
Got some parts, went to start the truck , no power ?
Trying fuse and batt , grounds nothen
Thinking Mabe some one messed w the truck while we were in the yard
I got pissed and hit the drivers fender , bam lights came on
Fired right up , but it was charge and then not charging
So got home , shaking wires found the weak link in the engine to cab connection
Fix all good. Long story. I hope somthin helps.