VTX running/brake light mod

Preface
This is the new and improved version of my old Tail Light mod. For those who have seen or done the old mod I think you'll be impressed with the improvements. I'd like to give a huge thanks to Pete AKA "Hambone" from the 1300 side of the VTXOA who took my design and made the first actual working prototype. Since I run aftermarket tail lights I needed someone else with the stock tail lights to be the "guinnea pig" before I unleashed this on all of you - he agreed and has run/tested the unit for several thousand miles through all sorts of conditions to make sure that no problems should arise based on the design. I also want to thank Ken (Guitar4Him) who helped me troubleshoot some problems I ran into during the design process of getting this circuit operational.
The old mod gave you red tail lights that made you more visible from behind using a single red LED on each side. This new mod uses 24 LED's for the tail lights (12 on each side). These will act as both running lights AND brake lights so you get additional brake lighting as well for increased safety. To make this even better we'll wire these up so that when you hit your turn signal the LED's will turn off and allow your stock incandescent turn signal to be seen as amber. If anyone has ever seen the Electrical Connection tail light mod, it's very similar - except theirs costs $50.

When I did my first mod I shopped around a lot and never really found exactly what I was looking for in LED's. On this project I teamed up with Custom Dynamics to get the best quality LED's and components. The LED's are Radiantz LED's and they come with a 5 year warranty. They are some of the best and brightest which means a better seen and brighter LED. In addition Custom Dynamics helped put a simple and easy "kit" together so you can buy all the electrical components from ONE supplier. This means you save money because you're not paying shipping on different parts from different places, discount prices because they buy the parts in bulk, PLUS the convenience of "one stop shopping" for the parts.

This mod will work on any VTX with the stock tail lights.

Preparation/supplies

Buy This electrical kit from Custom Dynamics, it contains:

24 red LED's
1 220 Ohm 1/4 Watt resistor
6 270 Ohm 1/4 Watt resistors
2 3 amp diodes
2 10 foot lengths of 22 gauge 2 conductor wire

1 small piece of plexiglass at least 3"x6". Most home stores will sell an 8"x10" piece for $3-$4. I recommend 3/32" or 1/8" thick, whatever you can find. You can check picture framing places for scraps and the internet is full of places that sell this as well. I'd check locally first so there's no shipping costs involved.

1" and 2 1/2" hole saws

Drill or drill press

Clear adhesive silicone, I used the marine vesion of "Goop" that I bought at Home Depot for a few bucks and it worked perfectly

Soldering iron & solder

Wire cutters and pliers

Electrical tape or heat shrink tubing or liquid electrical tape

Philips screwdriver

Process
First we need to get our plexiglass "donuts" prepared to mount our LED's for our circuit to. I found the easiest way to do this was to use a 2 1/2" hole saw in a drill press. This gives us 2 nice circles that are about 2 3/8" around and fit well in our turn signals. With the outside of the donuts cut out use the 1" hole saw to drill the middle of the donut out to accomodate the stock incandescent bulb. After drilling these holes you'll need to do a little sanding on one edge in order to accomodate the screw tab on the stock lens. This is what your final product should look like:

If you print out that picture it should come out to scale and you can use it as a template to make sure your "donuts" are coming out the proper size. The bottom line is that the donut must fit inside the stock signal lens

You can see the plexiglass in this pic because the protective coating is still on it, when the coating is removed you can barely see the donut.

With the outer and inner rings drilled you can make your marks for drilling where the LED's will go. Since we are mounting 12 LED's in each ring there should be one LED every 30 degrees around the ring. You can sketch your own template:

Or print this one which should also be to scale:

Do a little overlay and trace where the holes need to go:

Mark the holes:

And drill them out using a 13/64" drill bit:

I found that I got the best results be using a drill press at slow speed and "stepping up" from smaller bits to bigger bits until I got to the 13/64" bit. Too fast or too big of a drill bit can melt the plexi and/or crack it.

Wiring
This is the circuit we're going to be building on the "donuts":

Each set of 12 LED's is going to be mounted on a single donut, this will give us 2 donuts with 12 LED's on each. We'll break the procedure down into one donut and then you will just repeat the process for the second one.
It's important to note that LED's have to be connected a certain way - the longer lead coming out of the LED is the positive lead and the shorter one is the negative lead. Make sure to pay attention to this when connecting your wires or else your LED's will not work!!!
Since LED's are heat sensitive I use alligator clips for heatsinks to help pull the heat away from the LED. If you decide not to use the clips you must make sure you only apply heat when soldering in short bursts, just long enough to get the solder on the joint and then remove the heat.
When wiring these up we should use as much extra wire as possible since we'll need to "fish" the wires from the rear turn signals all the way to under the right side cover. Your kit from CD comes with 10' long wires which have a black and red wire in each. Use the red for positive and the black for ground when you wire yours. I used what I had laying around the garage for these prototypes which meant green and orange so remember that your wiring will look a little different from mine..

The final product will look like this:

And it is actually made of 3 "arrays" that consist of 4 LED's and a 270 Ohm resistor (you can see this in the schematic above).

It looks messy in the pics because I have already coated the connections with silicone to prevent any short circuits. If you look closely you will see the 3 270 Ohm resistors which start each array and then there are 4 LED's in series to complete the array. Simply mount an LED in the donut, CAREFULLY bend the wire leads into shape and trim the extra off. Do the same with the next LED (making SURE that you are connecting the long, positive lead from one to the short, negative lead on the other) and then add a drop of solder to make the connection.
Look at this pic from before I siliconed the circuit and you should be able to see everything better:

In this pic I had just finished soldering the LED's and was starting to connect the ground wire (remember I used green for ground, you'll be using black).

Now looking at this pic below you can see how I've routed the ground wire around the donut and made the connections where necessary. I have also added the 270 Ohm resistors in this pic in preparation for adding my positive wire.

As I progressed through soldering all the LED's I would use a toothpick to apply some of the adhesive silicone to secure them in place in the donut. I also used the toothpick and silicone as I made connections to ensure that the assembly was both watertight and would not short out on anything. When you have completed ALL the wiring you should take a few minutes to coat and seal the entire circuit with silicone to prevent problems.
Here is the finished product:

Back

Front

Lit for testing

Now that you have succesfully made one complete donut repeat these same steps to make another. You can test each donut when it is completed by touching the leads to a 12V battery (bike or car), just remember that LED's will only light when you apply power across them in the right direction, so when you test them make sure your red wire is positive and your black wire is negative.

With both LED donuts wired and working we'll turn our attention to making the setup that controls the running and brake light functions. This is the bottom portion of the above schematic that feeds power to both LED donuts. It consists of 2 diodes and a 220 Ohm resistor. Cut about 6-8 inches off of the 10 foot black and red wire to wire this up. Again my wire colors won't match yours because I used wire I had in the garage, you'll be using the wire that came with the kit from CD. Start by soldering one of your 6-8 inch pieces of wire to each diode and then solder the 220 Ohm resistor to one of the diodes. Make sure when you solder the diodes that the stripe end of the diode is AWAY from the wire.

You can see in the pic that the stripes on the diodes are AWAY from the wires and the resistor is connected on the stripe side away from the wire. You can also see that I'm using heatshrink tubing to cover the connections I've made as I progress, this is to prevent any short circuits. You can also use electrical tape, liquid electrical tape, etc to isolate and protect these connections. With that much done we'll make the last connection by soldering the resistor to the striped side of the other diode and adding another short section of wire coming out of the other side:

If you look at this setup you can understand how the LED donuts will function as both running AND brake lights. Under normal circumstances the LED donuts get power from the running light circuit which passes through the 220 Ohm resistor. The resistor dims the LED's slightly for normal operation. When you hit the brake light power goes through the other portion of the circuit bypassing the resistor and giving full power to the LED's. This gives us bright and dim functions in the same LED's and serves our purposes for running/brake lights very well.
Heatshrink or tape up the rest of the connections and once all the individual components are protected you can wrap the entire assembly to help protect it.

With our run/brake circuit and both "donuts" built we're done with all the prepwork away from the bike so we will move onto fishing wires on the bike.

Disassembly and routing wires
It almost took longer to fish these wires through the turn signal stems than everything else in this project, so have a friend around to help or at least to calm you down so you don't destroy the bike, lol.... I pulled the signal lenses off the bike by removing the one phillips screw under the housing:

With the lens off we'll go ahead and silicone the donuts into the lens so they're ready later. Clean the inside of the lens well using a little alcohol, allow it to completely dry and then run 4 little strips of silicone on 4 opposite spots on the lens, you can almost see them in the pic:

And then slide the donut into the lens to mount it:

Now set that aside to dry and we'll get back to pulling the wires.
Reach under the fender and you can use an 8mm socket to remove the signal posts from the fender. Remove the light holder assembly inside the light by pulling out the 2 little gold screws at the back and sliding off the assembly from the post. Make sure to take out the bulb first! (this is a recycled pic from my last mod so just ignore the LED and wires in the center of the housing). With the entire signal assembly removed and the lens off you can "fish" the wires from the donuts through the post (one donut on each side).

I used a small stiff piece of extra wire lubed with a little WD40 as a pull wire to help get the donut wires through. Once I got the wires through the stem I pulled all the extra wire through the stem and left about 3 or 4 inches extra wire in the housing for when you need to replace the turn signal bulb in this housing (the extra slack will allow you to remove the lens with the donuts to get to the bulb). Then I routed the rest of the wire under the fender all the way back through the grommet and under the right side cover (we need to wire them up in this wire harness):

You can see the grey wires in this picture routing from the signals and under the fender:

You will likely need to remove the wires from the "sheath"/insulation in order to get them pulled through the light stems, but once through you may be able to slide this insulation back over them (that's what I did with these). When running the wires from the back to the front of the fender just follow the course of the stock wires. There are several little metal tabs attached to the fender, you can bend these back to get the new wires under them and then bend them back into place. If you are unsure that the wires will stay at any point then just use a zip tie to fasten them to the stock wire bundle. I was able to get the wires all the way from front to back without dropping the tire (and I've got big hands) so I figure most folks should be just fine. If you run into any problems getting in there you can put the bike on a lift and let the tire hang down. If you still don't have enough room you can strap the bike on the lift, put blocks under the rear tire and remove the shocks. By removing the shocks the tire will hang even lower and give you plenty of room to work under there.
With the wires completely run and the silicone dry holding the donuts in the lenses you can reinstall the lens and the screw that holds the lens in place:

This is the finished product with the donut mounted inside, you can't even see the donut in there:

Now that we have the donuts installed and the wires run to the right side cover all we have left to do is the wiring in the wire harness:

Go into this wire harness and find the brown wire, light blue wire, orange wire and green with yellow stripe wire.
This is our "run/brake circuit" which we made earlier:

And this is how everything will be wired when we're done:

You can tap into all these wires however you see fit. You can solder or crimp new connectors or you can merely slide the wire into the stock crimp connectors and reconnect them.
What you want to do is connect:

Running light portion of the run/brake circuit to the brown running light wire

Brake light portion of the run/brake circuit to the green w/ yellow stripe wire

The output side of the run/brake circuit to the 2 red wires feeding the positive side of the LED donuts

The black negative (ground) wire from the left LED donut get's connected to the orange wire which feeds power to the left turn signal bulb

The black negative (ground) wire from the right LED donut get's connected to the light blue wire which feeds power to the right turn signal bulb

We can trace the circuit like this...
In order for a circuit towork it has to have power and ground. The LED donuts get power normally from the running light wire which is slightly dimmed by the resistor. When brakes are applied the LED donuts get full power by bypassing the resistor, this makes them brighten as brake lights should.
Now for the ground - the LED donuts get their ground through the turn signal bulb - but when the bulb gets power (when you turn on your blinker) it prevents the LED's from grounding and it makes them turn off.
This is the basics of how the circuit works and I hope it helps you understand what we're doing a little better.

Before pics

After pics

Running lights

Turn signal on

Afterthoughts
This is an inexpensive project when you consider the results. Like I said in the beginning, this mod is similar to the Electrical Connection tail light mod but it's a fraction of the price. The hardest part is fishing the wires through the turn signal posts, but even if you buy the Electrical Connection kit you still have to fish the wires and do the wiring yourself so you might as well save a few bucks in the process. It only requires some basic soldering skill to accomplish and it gives you a much brighter profile from behind which equals a safer riding experience.
This mod will work on any VTX with the stock tail lights and can be modified to work on any bike by just modifying the plexiglass donut to fit inside the signal housing and wiring it the same way (I've installed a set on a Valkyrie). Technically, this circuit will work on any 12V electrical system, so you could wire this any way you like for any application you see fit.