horn shorting out?

[dpd]

Hi all, I've got a small issue:
Turn signals, dash light, horn all went out at once. Blown fuse.
Replacement fuses blow until I disconnect the wire to the horn. So there is an electrical short in the horn?

Has anyone had this happen to them?
Thanks, David

[loki]

I have heard of the foam in the steering wheel degrading and the horn starting to activate all by itself (usually in the middle of the night), don't see how that could blow a fuse though.

[dpd]

With a multimeter I have continuity from the horn 12v wire to ground. But it's not just 'on'. As Loki says, it shouldn't burn a fuse anyway if the horn were just stuck on, so there must be something else...just hoping for a hint before I start taking the steering column apart!