"Tony Thomas" wrote in message news:47%mb.38895$e01.85121@attbi_s02...
Looks to me like the horn for the boat itself (like a car horn).

this may sound stupid, but why not put your ear there and blow your
horn and see if that is where the sound is comming from. that way you
can eliminate or confirm that it is the boat horn.
my experience with hot horns (and it is not worth much) is that on
some boats they go off for a second when you start the boat, like the
lights on your car dashboard to show that they still work, and on some
boats the hot horn only goes off when your engine is overheating.
my other question is, if you can not trace a colored wire back to it's
source, why do you want to know what it is? remember murphy's law
about if it ain't broke, don't fix it. you must be like me, I can't
help myself, always wanting to learn about things, but not really
there yet. good luck and enjoy boating along with the rest of us.