My '83 does this too until I knock it hard on the steering wheel. I guess it
is particles that fall down the horn switch and act up. My sister's '91
Jetta did the same thing.
Volkswagens, they do have character.

Entity  James Shinosky spoke thus:

> Hiy'all, the horn in my 88 Weekender suddenly goes on out of the blue
> and continues to blare until I unplug its fuse. I thought it was a mating
> call for other female vanagon somewhere (heh). It must be shortened somewhere
> between the steering wheel and the horn.
> Anyone out there please tell me the most common problem area of the
> horn? If it is in the steering wheel, please again tell me how to remove the
> steering wheel cover to access to the horn button. Many thanks!
>
> Jim
> W88kender
> Los Angeles