Many Motorcycle Turn Signal Circuits function on a 2 or a 3 wire system. Here we'll discover what the difference between the two is and how to make them work if you are trying to install 2 wire lights on a 3 wire system.

A three wire system consists of:

1. The Ground Wire (Usually Black or Brown)
2. The Positive Lead for the Flasher (This wire does NOT provide Constant Power)
3. The Running Light Wire (This wire does provide Constant Power)

A Two Wire System consists of:

1. The Ground Wire (Usually Black or Brown)
2. The Positive Lead for the Flasher (Does not provide Constant Power)

You can use Three wire Lights on Two wire systems OR you can use Two wire lights on Three wire systems. The only difference between the two is that a Three wire system acts as a running light also where the two wire does not. Please note that you will not be able to use the lights as running lights in either scenario. They will function only as blinkers.

Really the install is pretty straight forward, in both cases you would find the Running light wire, tape it off and tuck it away.

Q: I have a 3 wire circuit on my bike, how do I find out what wire is the running light wire?

A: If you don't have a wiring diagram I would start by attaching the Signals Ground (usually Black or Brown) to the Bikes ground wire.

After this it’s a matter of finding the wire that supplies constant power, you can do this by touching one of the two other wires to the Positive Turn Signal Lead. Turn your ignition key and engage the turn signal. Then touch the hot wire directly to the positive turn signal lead. When you find the wire that keeps your turn signals illuminated all the time (without blinking) then you have found the running light lead. This is the one we will tape off and tuck away.

When doing this make sure no wires touch each other or the frame of your bike if they do you will blow fuses.

It's as simple as that, now all you have to do is connect the signals to the other wire as you normally would and you now have turn signals.

Remember, don't try to use a two wire signal as a running light, they are designed as blinkers only. When used as a running light it will get way too hot burning out the bulbs or melting the light. (This does not apply to LED's, only conventional bulbs)

There are other ways of doing this, please leave any suggestions or comments by reviewing this article. Or if you want to grow this resource please contact us.