I wanted to convert my 1974 motorcycle lighting from the increasingly rare 6 volt system to an all LED system. This article focuses on the turn signals.
**NOTE** Some may notice I neglected to include a resister. I had plan to place it elsewhere in the harness, but I may just integrate it into the signal housing later (recommended). I also recommend using something more durable than cardboard to secure the LED in the signal's socket (step 9). I just use it because it was what I had on hand at the time; I'll be changing that later, too.
**ALSO** This is my first instructable, so if something is out of place, forgive me.
Here is the signal we'll be working on today. This particular lamp has two screws holding the lens to the signal body.
After the lens has been removed, you'll find the ancient 6v bulb snugged into the housing. Now would be a good time to remove the bulb. (I kept it in to explain the next step.) You may notice the bulb appears dark, or dirty. This is usually a sign the bulb is near the end of it's life. In most 6v systems, once a bulb blows out, it usually snowballs until they are all blown out. You'll want to remove the three screws holding the rubber bulb housing in place. Take note of the grounding wire held in place by one of the screws, take care not to damage this.
Note that the grounding wire is soldered to the base of the rubber bulb housing. This connects to the side of the bulb and grounds it through the body of the motorcycle, while the live wire makes contact to the bottom of the bulb. This completes the circuit and illuminates the bulb. We will be using the same concept to light the LED.
For this step, you'll need to clip the live wire and pull it through the signal body. Be sure to cut it so you have enough wire on both halves, should you need to reuse the connecter. For my specific application I do not need it, but I still like to give myself the option in case something changes down the road.
Now that the rubber housing is removed from the signal body, we begin to see just how simple this is set up. If you have not removed the bulb, do it now.
Now pull/push the live wire through the rubber housing along with the tension spring and plastic spacer. You will no longer need these parts, and may discard them now.
NOTE: Do not remove the original grounding wire, you will need it later.
Now, choosing a wire small enough to fit through the shaft of the signal body, cut a piece with plenty of length to travel through the shaft and out the housing. I cut enough to have about fifteen inches outside the shaft. This insures I have plenty of wire to work with later. You'll also need a smaller piece to attach to the grounding wire.
Now the fun part. Solder the live (longer) wire to the anode (positive lead) of your LED, and the ground (shorter wire) to the cathode (negative lead) of your LED. Go ahead and check the connections before shrink-wrapping. After that, go ahead and shrink-wrap the individual leads.
It isn't necessary, but I also shrink-wrapped the two leads together.
Now we need a way to keep the LED from shaking all over the place inside the signal body. All I had on hand was some cardboard, but i'm going to go back and use some heavy duty rubber, and glue it all in. I just needed something temporary. For now, you get the picture.
Whatever you choose though, it needs to fit snug inside the space the bulb use to take up.
Take a moment and check that everything is still working right.
Finally, solder the grounding wire from the LED to the original grounding wire.
Insert the three screws securing the rubber housing to the signal body. Make sure the screws are snug to insure a proper connection to ground.
Success! With the live wire connected to a power source, and the body grounded, the LED fires perfectly.
Once again, you're going to want a resister somewhere in the loop. I'll probably go back and put one in-line with the live wire. Keep in mind each application is going to be different. This signal is off of a 1974 Suzuki, but I imagine the concept is similar across the board.