My old horn used to sound pretty good a few years ago before I started this restoration. I rewired the truck to 12-volt and replaced the horn wire and all associated parts in the steering column. When I hooked up the battery and checked lights, I had everything. The horn barely sounded, though. I touched the outside cover of the horn relay and got sparks. From the diagram, everything is hooked up right. I disconnected the battery negative cable and I still have power at the horn relay. I had a little smoke there as well and am picking up a new relay at NAPA this morning. Any ideas what might be wrong? I'm not seeing anything that says something needs to be wired different for a 6-volt horn to work on a 12-volt set-up. And I'm wondering why I still have power at the relay with the battery disconnected. Thanks.

1953 Chevy 3600 3/4-Ton