LED Tail light problems

The problem is an easy fix. You will have three wires going to the light bars you will have the negative and two positives. One coming from the running light circuit and the other from the stop light circuit. install a 300-400 Ohm resistor in the running light wire. 300 if you want it a bit brighter or 400 if you want a greater difference in the intensities.

mtbspeedfreak wrote: Hey guys,

I made a custom tail light for my touring trunk- I ordered three 6x6 LED lights (on a flat circuit board) from superbrightLEDs, with an 1157 plug end. Today, I wired them together, but when I plug the light in and turn the ignition on, the tail light just turns on at full intensity- it does not get brighter when I hit the front or rear brake (on the battery or while the bike is running).

I am 100% positive that the lights are all wired together correctly, and I spent most of the day working on doing it the right way- solder and heat shrink tape.

Do I need to throw a resistor in somewhere? I have the brake indicator light pulled from the front because LEDs set off the bulb out warning.

Any suggestions?

The terminal closest to you in this picture is the "STOP" light the farthest is the running light. Install the resistor (300-400 Ohm) in the circuit connected to the farther terminal.

otakar wrote:

mtbspeedfreak wrote:

The terminal closest to you in this picture is the "STOP" light the farthest is the running light. Install the resistor (300-400 Ohm) in the circuit connected to the farther terminal.

For further clarification, when I have the 1157 plug end horizontal (i.e. the bungs on either side are horizontal), the running light positive terminal will be the one closest to the "deepest" bung (i.e. the bung closest to the base of the plug end), right?

If the top lock lug is the closest to you, than the terminal on the left is stop and the one on the right is Running light.




The "RED" is the "STOP" terminal

otakar wrote: If the top lock lug is the closest to you, than the terminal on the left is stop and the one on the right is Running light.

Attachment DSC02453.JPG not found

The "RED" is the "STOP" terminal

Attachment DSC02454.JPG not found

Thanks a lot Otto! You're the man!

No Prob. Man

mtbspeedfreak wrote: Hey guys,

I made a custom tail light for my touring trunk- I ordered three 6x6 LED lights (on a flat circuit board) from superbrightLEDs, with an 1157 plug end. Today, I wired them together, but when I plug the light in and turn the ignition on, the tail light just turns on at full intensity- it does not get brighter when I hit the front or rear brake (on the battery or while the bike is running).

I am 100% positive that the lights are all wired together correctly, and I spent most of the day working on doing it the right way- solder and heat shrink tape.

Do I need to throw a resistor in somewhere? I have the brake indicator light pulled from the front because LEDs set off the bulb out warning.

Any suggestions?

LEDs require a series resistor, to make them "dimmer" you use a larger resistor. The 3W Luxeon "dual filament" LEDs I run have only ONE LED inside, but two different series resistors from each power line to give two different brightness levels.

Motor Head wrote: So they will have the same brightness then. Either re-order or use a resistor to drop the tail light circuit.

If you look at the back of the boards, there are already resistors (as there MUST be to use LEDs). To make a "dual brightness" bulb, just run the 12V line for the "dimmer" usage (the running lights) through another resistor going into the LED power line. The power for the "bright" light (turn signal or brake light) should run straight into the power feed with no added resistance, just the resistors you already have on the board. You may want to add series diodes (1N4001)in each power line so they don't cross talk, ie have the brake lights power the front running lights or vice versa.

I threw in a 330 ohm 5 watt resistor and that did the trick.

Thanks guys!