[movin]

I just changed my radio head unit and when I turned it on everything was fine except no AM reception. It sounds like the antenna was not connected but it is, except for the small black wire that is sheathed with the antenna coax lead. I found this small black wire just dangling, not connected to anything. Is this the problem? Where does this wire connect to? I tried the old unit, same thing, lost the AM stations. What could be the problem???
I traced the antenna coax cable back to a small block where the black wire is also connected and there is a wire from the windshield that connects to the block also. Any help appreciated!