Bonneville America Forums Forums Technical Forums General Tech Turn signal wiring

OK, got some new turn signals. They have three wires vs. the stock two. How do I hook 'em up? Sorry, I'm even a worse electrician than I am a wrench.

Seems to me I had the same problem when I put my aftermarket signals on.If memory serves I believe the third wire was an accessory ground.If you take the lens cover off perhaps you could tell.On the bike side you'll need to know which wire does what to tie into the new light.Don't have my manual handy so I can't tell you the color codes but I know somebody else will chime in.

3 wires, presumably a 2 filament bulb of different wattages [e.g. 5/21w] and an earth... Just wired my new indicators in and I only wired in the brighter higher watt one...

Thanks for both the responses. I think I've got this one figured out.

when I rewired my turn signals to go from single element bulbs to dual element, it was necessary to add a ground wire as the OEM wiring is not set up that way (it has a ground, just not handy to the signals)

One wire is going to be ground (earth), probably black or green. The other two are running light and flasher. Usually, the flasher will be red or orange and the running light brown or yellow. To be sure, ground one and connect another to 12 volts, then disconnect it and connect the third wire to 12 volts. If one combination is very dim, the wire that is grounded shouldn't be. In that case, ground another wire and try again. When you hit the combination where one wire on 12 V is bright and the other is brighter, you have the right wire grounded and the one that makes the brightest light is your turn signal.
If you want to use the running lights, find the 2 connectors that go to the handlebars and tap the running lights into the blue wire that runs between the connectors. This is the wire that connects the main light switch (a jumper plug on bikes for the North American and some other markets) and the dimmer switch.