A horn provides an audible method for alerting other boats or swimmers to your presence. They are necessary for safe operation of any vessel in all waterways. Wiring for a boat horn is a simple electrical circuit with a switch. Protecting the wire connections from the elements with a tight wrap of electrical tape assures they don't corrode due to water penetration. Installing a boat horn is a simple process once you understand where to connect the wires.
Strip 3/8 inches of insulation off the horn's positive and negative wire with wire strippers.
Run a section of black wire from the horn to the boat's battery and cut to length. Strip 3/8 inches of insulation off both ends of the wire.
Connect the black wire to the negative wire at the horn with a butt connector. These work by placing one wire in each end and compressing with pliers.
Loosen the negative terminal on the battery. Slide the black wire underneath and tighten it down.
Run a section of red wire from the horn to the switch, then to the battery and cut to length. Strip 3/8 inches of insulation off both ends of the wire.
Connect the red wire to the positive wire at the horn with a butt connector.
Loosen the two terminals on the switch with a screwdriver. Cut the red wire at the switch's location and strip 3/8 inches of insulation off the end of both wires.
Connect one wire to each terminal on the switch and tighten them down.
Connect the red wire at the battery to the fuse holder with a butt connector. Loosen the positive terminal on the battery and slide the fuse holder's wire underneath. Tighten down the terminal.
Install the horn manufacturer's recommended size fuse in the fuse holder by pushing it in.
Wrap all of the connections with electrical tape and secure any loose wires with cable ties.