The Yamaha Road Star Warrior Forum

  So I saw a post in the mods list for a DIY tail light, but when I looked it was complicated and the video was down. So I thought I would make one for cheap and post the how to.

To keep it simple, you can wire 2- 12 volt relays to your taillight to blink each side off. Each 1/2 of the stock taillight is 35 ohms,  so if you turn one side off, you need to balence the circuit resistance to keep the voltage to each LED the same. Otherwise if you just split the thing in half, you will send too much voltage to each one and burn them out.

Materials:

    * 2- 12 volt 5 wire relays. I used DEI 525T relays that can be had at Best Buy for $10 each. These are 40 amp relays and are way too big for this project.If you can find smaller ones, use them. They need to have 1 normally open and 1 normally closed connection.
    * 2-35 ohm 1/2 watt resistors. Radio shack 271-1104 These are 33 ohm, close enough.- $1
    * 2 Small ring terminals - $1
    * Solder, heat shrink tube - $free I had this stuff already

Take your tail light off, and split it apart using a Dremel. Remove the LED assembly:



Next, wire up both relays.

RED> SOLDER, Connect to the positive of the blinker.(Brown is left, Green is Right - Coordinate with the YELLOW wire connection)

BLACK> SOLDER, Connect to ground on the blinker (black)

YELLOW> SOLDER For the RIGHT side, connect the yellow to the BLACK wire in the tail light that was screwed to the LED plate. For the LEFT side, connect the yellow wire from relay 2 to the WHITE wire that was connected to the LED plate.

BROWN> SOLDER one 33 ohm resistor to each brown wire. Loop the other end. The looped end will land under one of the screws that holds the LED plate in the assembly.

ORANGE> Crimp a ring terminal on each orange wire.

You will get something like this:

Cut a V shape in the middle of the LED plate and back plate to give yourself room for wires.

Here is a diagram of exactly how to connect each of the wires:


Here is what it looks like all put back together:


Connect your blinker and tail light connections back:


Test your blinkers. Then glue your tail light assembly back together and mount back on the bike. Trim all of the extra blinker brackets off and mount your license plate somewhere else.

All done!! I hope this helps someone else do the same mod.

VERY Kool!!!!!

SWEEEEEET!!  Hope you don't mind I added this to the DIY Mod List and my own mod list.

 No problem. That is why I did it!

Very, very cool...

 Cool stuff right there. I will have to do this sometime. Thanks!

That's awesome!

Good-bye to Clear Alternatives!!

Where and how did you mount and hide those two black boxes?

 Maybe I am not seeing something but it seems to me that you are shoving 14 volts across the pack of leds when the left side is lit up. You have the left wire on the bottom of the circuit.. the leds on the left side would be uneffected by that. I am confused. I did mine myself but your circuit just makes no sense to me. Maybe I just need to see a more clear diagram.

 Were did you come up with 35 ohms also? Just confused here. Good to see another mn rider!

The 2 black boxes, relay packs, are hidden in the tail light housing. There isn't much room, so I recommend getting relays smaller than 40 amps.

As far as the 35 ohms, I measured the Voltage and Amperage across the light when it is on, both brake and running lights. 

The LED's don't get 14 volts. The coil of the relay gets 14 volts. The yellow common wire of the relays gets its voltage from the circuit built into the stock taillight (black and white wires) These wires put out 8.5V during braking. The amperage is .122A. This is real measured values for the light under normal operation, with no mods. If you use the formula OHMS=VOLTS/AMPS you get 8.5V/.122A=70ohms.

The tail light in a basic sense is 2 banks of 8 LEDS in series. Resistance (ohms) in series is added straight up. R1+R2=Rt  Where Rt=70

Since both sides have the same number of LEDS you can take Rt/2. 70/2=35 ohms.

If you follow the picture of the circuit, when the Left blinker is turned on, it turns the left side on and off**. When the left side is off, the Positive connection for the LED's electronic assembly (white) passes through a 33ohm resistor, through the yellow wire on the left relay connected to the White wire in the LED electronics assembly. The reverse happens when the right is activated.

At first I didn't get it either, and this was my third draft. The other 2 were way more complicated but this was the easiest, cheapest, and quickest.

**In a relay, the voltage applied to the coil does not pass through the YELLOW, BROWN, and ORANGE wires. The coil just flips the switch back and forth depending on if there is power. The yellow wire supplies power to either the orange or brown depending on of the coil is on or off.

Hope this helps. If anyone needs more info, ask away!!

Ben....excellent instructions & technical explanation of the taillight LED circuit.. thanks!

The accompanying detailed photos & wiring diagram of your creative mod should make this task possible by many members …. nice job .. and great sourcing to find the SPDT relay with the 5-pin wired socket @ Best Buy . Most automotive stores carry a relay with just a normally open contact.

 what an awesome mod! great write up with pics. think i wanna try it on my spare.

 I see now. I was looking at this a completely different way. Never thought of doing it this way. Good thinking!

For  a smaller relay go to any automotive place and ask for a small ford style fuel pump relay. Would think its not even 1/2" thick.

 The more I take a 2nd and 3rd look at it, I wouldn't use the BB relays. They are just too big, in amperage and size. The idea of a fuel relay would work just fine as long as there is 1 NO and 1 NC contact in each.

At BB, the relays are kept in their install bay. You can't get them unless you ask for them.