Attachments :
Proper electrical hookup for loud, heavy duty electric horns is
important
for maximum effectiveness and safety. The stock wiring harness is
inadequate to handle the electrical demands of accessories that
draw
large amounts of current. A horn/head light relay is a heavy
duty
switch that handles large electrical loads safely and provides
maximum
current to reach the accessory. The relay is an electro-magnetic
switch that allows a light duty switch (like a horn button) to
control
much more current. When the switch is pressed, an electro-magnet
closes the circuit allowing a second circuit to pass larger
amounts of
current to the accessory.
Stranded 14 gauge electric wire is used to connect the relay to
the
12 volt power source and to conduct the current to the
accessories.
Thinner 16 or 18 gauge wire can be used the handle the lesser
amount
of current that is used to turn the relay on or off.
Disconnect the wire that goes from the horn button to the stock
horn
& run a new wire from the disconnected wire end (at the horn) to
the
trigger-circuit terminal of the relay. The 2nd trigger terminal
on the
relay is connected to a 12 volt power source using 16 or 18 gauge
wire.
Pressing the horn button will result in an audible click from the
relay,
indicating that the relay is wired properly.
The heavier 14 gauge wire is connected from a 12 volt source to
one of
the remaining relay terminals. The last terminal is connected to
the
horn(s). The final hookup is to use 14 gauge wire to connect the
2nd
horn terminal to a chassis ground, using an eye hook electrical
connector.
The attached wiring diagram is a generalized setup for horn
relays.
Auto parts stores sell all the parts you will need to complete the
setup.
A similar setup can be used to control the high & low beams using
the
stock headlight switch. A DPDT (double pole, double throw) relay
or
two 'regular' relays would be required for the headlight setup.
This
setup would allow more current to reach the headlight, resulting
in more
light output. This is important for those running more powerful
(higher
wattage) headlight bulbs
Additional installation tips:
Buy a relay that has the relay's wiring diagram embossed on the
relay's
housing. Make sure that all wires connected to the relay can't
accidentally
short out against the frame.
On my KLR, I mounted the relay to one of the 6 mm bolts that
attaches to
the fairing's flat plastic (rear) headlight cover. This minimizes
the length
of the wires and keeps the relay relatively protected.
Mount the horn so that water can't be trapped inside the horn.
Tilt the
horns downward so that the opening points about 10 feet in front
of your
bike. This will maximize sound reflection in front of you and
allow water
to drain out.
Use 3/4" X 1/8" steel flat stock for the horn mounting brackets.
Aluminum flat stock should be avoided because it will fatigue and
eventually break.
To use the 'polite' stock horn, run a new wire from the
disconnected (stock)
horn terminal to a new momentary-on pushbutton switch. The second
terminal on this new switch will be need to be grounded.
Professor A9 Federal Way, Wa. [USA]