I am just opening that contactswitch and thinking what is that material between plates (that black rubber).maybe i clean that away and try again.If you're saying that you have intermittent horn action because the contacts aren't working, try cleaning them with a good cleaner that is designed for rubber as well as metal. I use this:
http://www.all-spec.com/products/F100L-L2C.html
You'll also find some good aerosol cleaners on that site.
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