Led for original trunk lights

[Hendrix40]

Anybody been successful at this. My first attempt at plug and play resulted in the bright stage (brake lights) on all the time.

 

[Scott-E]

Anybody been successful at this. My first attempt at plug and play resulted in the bright stage (brake lights) on all the time.

You need blocking diodes in the power leads going to the LED lights. Most LED lights do not come with them so the taillight circuit will back feed power into brake light circuit. Those LED lights use resistors to feed the same LEDs used for both tail and brake light functions. Filament type tail and brake light bulbs use two different filament elements so the two circuits are isolated from each other. Some LED lights come with blocking diodes so they work out of the box, but most do not.
The picture below shows one diode being used but I ended up with diodes in both the tail light and brake light lines feeding the LED bulb in all four of my trunk lights. Adding the diodes does reduce the brightness of the lights.

Later I made up a new in trunk wiring harness to feed my 4 LED lights. I wired the 2 inner lights as tail lights only. Then I wired the 2 outer lights as brake and turn lights only. I did that so when the outer light is flashing a turn it goes completely dark between flashes. It makes the brake and turn signals stand out much better to drivers behind me. Doing it that way also eliminates the need for those blocking diodes.

 

[Hendrix40]

You need blocking diodes in the power leads going to the LED lights. Most LED lights do not come with them so the taillight circuit will back feed power into brake light circuit. Those LED lights use resistors to feed the same LEDs used for both tail and brake light functions. Filament type tail and brake light bulbs use two different filament elements so the two circuits are isolated from each other. Some LED lights come with blocking diodes so they work out of the box, but most do not.
The picture below shows one diode being used but I ended up with diodes in both the tail light and brake light lines feeding the LED bulb in all four of my trunk lights. Adding the diodes does reduce the brightness of the lights.

Later I made up a new in trunk wiring harness to feed my 4 LED lights. I wired the 2 inner lights as tail lights only. Then I wired the 2 outer lights as brake and turn lights only. I did that so when the outer light is flashing a turn it goes completely dark between flashes. It makes the brake and turn signals stand out much better to drivers behind me. Doing it that way also eliminates the need for those blocking diodes.

Thank you I knew it had to be something like that. I'm actually changing my bike taillight/brake light first so I assume the same principle applies, correct? How did you get the turn signal wires to the trunk? Do you have a diagram?

 

[Scott-E]

Thank you I knew it had to be something like that. I'm actually changing my bike taillight/brake light first so I assume the same principle applies, correct? How did you get the turn signal wires to the trunk? Do you have a diagram?

I wired them into my trailer light 5 to 4 way turn, tail, and stop lights using a relay type adapter. The relays also provides isolation between the bikes wiring and the trailer and trunk lights. I'll post the diagram for the circuit from a post on a Honda Goldwing forum.
The trunk originally came with a two wire molex connector in the trunk serial number and information data plate and a two wire pigtail that connected to the taillight wire and ground. I enlarged that hole so a 6 pin molex would fit. I used a 6 pin plug because I already had one. Just about any plug with 4 or more wires will work. I'm only using 4 of the 6 pins on my connector so I could use the extra 2 wires for some sort of electric or electronic device later. When I enlarged the hole in the data plate for the connector I drilled out the rivets and removed the plate, fit the connector in it, and then riveted the plate back on the trunk. The small wiring harness I made for the inside of the trunk is easy to make. Just connect the white ground wire to the bases of all 4 lights.
The brown wire is connected to the taillight (low light output) LED bulb through the light sockets on both inner 2 trunk lights.
The green wire connects to the brake/stop (high light output) LED bulb through the light socket on the outer right side trunk light.
The yellow wire connects to the brake/stop (high light output) LED bulb through the light socket on the outer left side trunk light.
If you ever want to add a trailer hitch to your bike you can just "Y" off another set of trailer harness wires to the wires before they go to the trunk and use a standard 4 way trailer connector.

 

[Alan F.]

This is the clearest diagram and explanation I've seen for this situation, thank you very much.