Topic: LED brake light woes, my main fuse is blowing, what did I do wrong?

[leesfer]

In the process of installing an LED brake light on my CB750

The wires on the brake light are yellow, black, red. I assumed black is ground, red is tail, and yellow was brake

So I have black going to bike's green, red going to red, and yellow going to bike's green/yellow. I also have a resister between the light's yellow and black wires.

However the light works when the bikes ON, but if I hit the brakes, the brake light does not come on and I blow the main fuse.

What did I do wrong here?

[Don R]

Black is 12V. green is ground. Make  a test light and check them.

[leesfer]

Black is 12V. green is ground. Make  a test light and check them.

That's how I have it, the black from the light going to the bike's green

Could it be the resistor or something else?

[Bodi]

I hate that word "assume" - it usually makes an ASS out of U and ME. Test the dang light and find out what each wire really does. Try the brake with the new lamp disconnected, you may find the problem is unrelated.
And those parasite connectors suck. Plus your red wire is almost broken (with the conductor exposed!) from using and removing one of them.
Plus the male bullets you have are not insulated, and can (will) short to ground if left as-is, they need to be wrapped in electrical tape at the least (heat shrink covering the exposed metal bit would be better). No offense, this just looks like trouble brewing in the future. If it worked, that is.

[leesfer]

I hate that word "assume" - it usually makes an ASS out of U and ME. Test the dang light and find out what each wire really does. Try the brake with the new lamp disconnected, you may find the problem is unrelated.
And those parasite connectors suck. Plus your red wire is almost broken (with the conductor exposed!) from using and removing one of them.
Plus the male bullets you have are not insulated, and can (will) short to ground if left as-is, they need to be wrapped in electrical tape at the least (heat shrink covering the exposed metal bit would be better). No offense, this just looks like trouble brewing in the future. If it worked, that is.

Don't worry about how the wiring is done right now, they will all be insulated with heat shrink. Plus, they are all already covered in a clear plastic from the female end, nothing is grounding out. Let's focus on the issue itself.

That's nice that you don't like the word "assume", I've already tested the lights, my assumption was before testing and confirmation. It's pretty obvious what three wires coming from a modern light are going to do anyway. You really think I didn't test the light before starting to solder?

There was really no need to be a jerk, no wonder so many people told me to stay away from this forum

[Don R]

 Sorry, I thought you had black from the harness going to green. It's pretty hard to tell from your picture because I can't see where the colors are going to / coming from.

Maybe you can educate me, what does the resister do? I know we use them on turn signals with LED's but I don't know about this.

[leesfer]

I've gotten it figured out, sorry for the bad picture.

The resister was screwing things up, I am going to have to look into that more for LEDs

Once I removed the resister from the wiring everything is working flawlessly, but I worry about it without a resistor in there somewhere...

[Don R]

I edited my post, asking about the resistor.

[leesfer]

It's because LED's are semiconductors and they will draw as much power from the source as they possibly can and they can kill themselves that way, a resistor is in there to keep things steady

That's the abridged version

[jonda500]

Oh? I thought that only led blinkers required resistors in order to add to their measly power draw(0.3amps) and bring it up to the nearly 2 amps each that standard blinkers draw 'cause otherwise with only .6amps going through it the flasher can wont flash!

[leesfer]

Yeah the blinkers definitely need resisters or just an electronic clicker will work, too I believe

As far as I know, any LED brake light will need a resister to keep it at a lower draw than its peak so it doesn't burn itself out

[TwoTired]

If your selected LED example requires a resistor, it must be in series to limit current flow through it.  Some "LED assemblies" already have a resistor incorporated to save it from being fried by unknowledgeable consumers.

Not all "LED lights" are equal.

If you are trying to mimic the electrical load of an incandescent, then you need a resistor in parallel with the lamp as well.

[leesfer]

Thanks for the info, I need to check into my lamp and see if it already has a resistor built into it, that might be the case