why does horn blow as battery dies?

As my battery was discharging in the garage (it just won't hold a charge anymore, been drained by stupidity a couple times), the horn turned on all by itself. I thought I might have an electrical problem other than battery health, until I read on an old post a guy describe the sound of his battery dying as including, "the horn blows." Why would the horn circuit activate when a battery is dying? I searched this forum and Google but couldn't figure it out.

That is pretty odd. I did a search and found a wiring diagram for the bike. The button is connected to ground so the horn has power to it whenever the ignition is on.
Someone in my bike's history replaced the horn with one from a car. The body of that horn feeds the ground. Then they wired a relay into the system and the horn button controls that, which feeds the power to the horn.
I know that wasn't any help but I'm sure one of the electrical guru's will chime in and give you the answer you need.

Post edited by: The Milkman, at: 2008/01/27 13:05

If the wiring is good and in original configuration, the horn won't blow by itself as the battery dies.

You probably have a short somewhere. When the horn blows because of the wiring problem, the horn is what kills the battery.