LED tail bulb not working?

[the_nutt]

I'm running this tail light and trying to use this bulb on my '72 XS2. I've gotten the light to work correctly with the incandescent bulb, but get NOTHING when I try to use the LED bulb. I have also tried plugging in these resistors I bought on a whim a while back, but still nothing. My bike is running from a capacitor, kick only, PMA and PAMCO. Anybody have any advice for how I can run an LED bulb in this socket/light?

Thanks,
Cody

 

[Grinder]

try hooking the led bulb up to a battery and see if the bulb works first. Some of those cheap bulbs are real junk. The 1157 led I have in my taillight was 3X that price but works great.The resistors are not needed for brake/taillight, only for turn signals.

 

[XSLeo]

Ok your incandesant bulb is not polarity sensetive. Hot and ground can be hooked either way and it will work. An LED is polarity sensitive so the hot and ground have to be right. Adding resisters won't help.
Check you bulb socket, make sure that the two wires going to the center are the hot wires. If it has a third wire this is ground you need to check to be sure it gets continuity from the wire to the outside of the socket.
Leo

 

[the_nutt]

try hooking the led bulb up to a battery and see if the bulb works first. Some of those cheap bulbs are real junk. The 1157 led I have in my taillight was 3X that price but works great.The resistors are not needed for brake/taillight, only for turn signals.

Thanks, I'll check the bulb and look into a higher quality one.

Ok your incandesant bulb is not polarity sensetive. Hot and ground can be hooked either way and it will work. An LED is polarity sensitive so the hot and ground have to be right. Adding resisters won't help.
Check you bulb socket, make sure that the two wires going to the center are the hot wires. If it has a third wire this is ground you need to check to be sure it gets continuity from the wire to the outside of the socket.
Leo

This is what I needed to hear. I found another thread where someone had a similar light with the same black, red, and yellow wires. He assumed the same way I did that black was ground. I'll look at the socket and ensure polarity is correct.

Thanks guys, I'll check back later tonight with results.

 

[the_nutt]

XSLeo you hit the nail on the head. Turns out yellow was the ground, not black. Switched em and now it works perfectly. Still going to look into a higher quality bulb too.

 

[Grinder]

Glad you got it figured out. I tried a cheap bulb first that a friend had and it was very dim. The one I'm using now is equal or brighter than a regular 1157.