Washing your engine without sealing electric connections is never a good idea. There are just too many electrical/electronic parts that are prone to water intrusion and eventual corrosion.
If your horn is not sounding normal, there is a small chance that it can be removed and dried out with low-pressure compressed air, but I believe that you will need to replace the horn itself.
Look around the ashtray for the latching mechanism and lightly lubricate it. It may be toward the back of the opening.
I sincerely hope that all of this advice has been helpful, and any donation would be appreciated as I, and my fellow experts, provide our time and professional advice on a volunteer basis.
Friday, October 7th, 2011 AT 4:00 PM