My 2000 Jimmy's horn would blow at the carwash along with a head scratching list of other issues. I traced the wiring harness from the under hood fuse block towards the firewall. It runs along the wheel well and was shorted, burnt and corroded on the corner of the bracket that holds the abs motor. It's not easy to get to or even see. But it's worth a look if you're under your hood. I hope this saves someone the embarrassment of a honking horn or having to be home when the street lights come on because your headlights don't work.

 

Rusty, you ought to post your findings above in your Original Post. That is helpful for future folks when they do a search for the trouble 'horn blows -----' and they will be able to find this info easier. Otherwise they will find the post will no solution. Thanks!

 

Thanks Jim. I don't use computers much and this is the only forum I've ever joined. I have a lot to learn. Actually, you are one of the people whose posts I've found helpful. Thank you.