This can be caused by a variety of things. As mentioned already, it can be caused by an accidental key in the gap on the steering wheel. Or it can be caused by simple wear on the contact ring or on the horn contacts. It can be caused by a failure in the turn signal stalk. The newest of our North American Vanagons is 22 years old, so wear should not be unexpected. 

On Mar 2, 2013, at 10:52 AM, Suzy Wojcik wrote:

> Went out to the garage and climbed into the Westy. Put the key into the
> ignition and turned her on and the horn started blaring away. Turned her off
> and it stopped. Then back on again, and no horn. So, what is going on? Second
> time this has happened. I seem to remember a post recently about lubricating
> the horn ring? Where? Wetwestie or the Vanagon list? And with what? WD 40?
> And, what part of the horn? Thanks for any help.
> 
> Suzy Wojcik
> 87 Westie
> Dove Blue, Bluebelle
> Eugene, Oregon