Hazard warning flashers have many uses for road users:
Some use them to park illegaly and try to fool the parking attendant that "They'll only be a few minutes"...
Blonde airheads driving sugar-daddies or husbands SUV's, unable to find a parking space that will fit both their behemoths and suit their lack of parking skills, stick them on to park up the kerb on any old street corner or in a pedestrian crossing. In front of schools an speciality.
Also, at least here in Spain, slow vehicles, like heavily-laden trucks going up long highway inclines, or vehicles with mechanical problems use them to warn approaching traffic to be ready for overtaking them.
Another use is to turn them on when approaching some sort of hold-up to warn following traffic that they're slowing down. This is also useful. It's surprising how disciplined people are when using this feature. The first car that turns them on will turn them off when the following car turns theirs on and so on, so you don't have a forest of flashing lights. This can avoid being rear-ended.
Silly motorcyclists that enjoy a ciggie on the move will find them useful when stopping on the side of the road to light up...errr, Oh, that's me I'm afraid . It's bad enough trying to light up in a strong wind without being also rear-ended by some blind motorist.
I have no use for hazard lights to park with the engine off. I always park off road and the bike's battery wouldn't tolerate flashing lights for very long without discharging and leaving you stranded, but I would like them for reasons 3,4
With this in mind I've devised an extremely cheap, quick and simple way to provide me with this feature without going to the expense of a proper unit like the Signal minder SM-1 that also has a auto switch-off feature, costs a cool $110 and you'd have to read through the 38(!) page instruction manual...or complicated mods to the wiring.
You need a simple on/off switch that can be placed in a convenient position and doesn't look too much out of place. I've found a source of engine kill switches that fit 22mm (7/8") handlebars. They're sold to provide an engine stop switch to enduro and motocross bikes, and are of the "normally open" type, that's normally open when the button is at "OFF". Just what we need.
The whole thing is so easy that it has taken longer to type this than to fit it. All you do is choose a location for the switch, open the headlamp shell and locate the positive feed wires to both the front flashers. They're Green/white and Green/red.
Shorting those two wires together with the added switch brings on all four lamps together, but only when the normal flasher switch is used as well, this is the only disadvantage of this system. No great deal though.
Don't worry about overloading the flasher unit. You'll notice that the markings on it say something like: 2(4)x10w
means that it can operate either 2 or 4x 10w lamps. This is of course necessary for cars that normally have OEM hazard lights.
I have located mine close to the normal flasher switch close to the left switch cluster. I could have fitted it right next to the switch cluster rather than the clutch lever anchor bracket but then my Napoleon mirrors would fit further inside the bars making the rear view worse. Those of you with bar-end units can do it.
The disadvantage is that both switches have to be operated for the 4 lights to come on. As these hazard lights are not for use when leaving the bike parked, this is not a great disadvantage. When you feel that they're going to be needed you first flick the auxiliary switch ON and then when you need them operate bike's flasher switch either left or right as normal. Or the other way round.
There are ways of providing proper car-like hazard lights that work on just one switch wether the ignition is on or not, but they're a lot more complicated.
Examples of sources for these switches. Price ranges from $6.90 to $17.86 for the same switch (In the UK).
Search ebay for something like "kill switch" or "handlebar switch"
Cost £10.95 ($17.86)
Another at $7.44:
And this one at $6.90: