Check to make sure the hood switch isn't knocked out of place. This happened to me. It's up on the firewall and it should be tightly snapped into place.
Try resetting everything by disconnecting the battery for a minute (but make sure you know your radio code first!)
Also, you can pull your fuse for the horn to silence it. You'll want to find the issue because you also won't have a horn while driving which is dangerous, but this is at least a way to stop being a neighborhood disturbance while you fix it.
1995 RRC LWB Beluga Black, 4.6 engine
1991 BMW 318i
1988 Saab 900 turbo convertible
1976 BMW 2002 (in progress)
Ford Crown Victoria Police Interceptor (various years)
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