horn help please.
 

Hello everyone! I have a problem with 2000 century's horn. It is not working checked relay, then while I was taiking it apart to look for something wrong I saw what the black wire that looks like it's disconnected to something. I had replaced the turn signal in 6 mnths back and am not sure if it is something I forgot to reconnect or if it's some thing just disconnected now.
Can someone please help and tell me if this wire is part of the horn? Thank uou