Topic: tail light wiring?

[slowjo]

I'm trying to wire a Lucas style tail light for a 1972 CB750. When you step on the brake the light lights up both filaments. When you turn on the headlight the light lights up one filament. When you turn on the headlight and step on the brake only one filament lights up and its not as bright. The Lucas tail light has only two wires. One black. One red. I ran the red wire to the stock brown wire. I ran the black wire to the stock green wire. And I ran a ground wire from a bolt that holds the tail light to the fender and ran it to the stock green wire with a yellow stripe. Both lights work great separately but not at the same time. Is there something I'm doing wrong.

[Duke McDukiedook]

Green is ground.

[Patrick]

The two wires from the light are probably hot wires that run to each filament in the bulb. I would try hooking one wire to the tail light hot wire, the other to the brake light and then run a ground wire from the light to the frame.

Patrick

[Spanner 1]

Patrick+1, both wires are hot for each bulb filament ...a ground wire from this light would go to green on the bike... black should be taillight and would go to brown on the bike and red should be brakelight and goes to green-with-yellow tracer...if wrong...swap red and black..l8r.

[slowjo]

Thank you Patrick and Spanner. I ran both wires as hot and the light works. Now I'm one step closer to getting back on the road. Thank you again.

[Duke McDukiedook]

No love my way? I gave you a third of the equation 
**sniff, sniff** No man, I'm OK, really man. 

[Patrick]

You could run the ground from the light to the green wire, Spanner, but you also can go to the frame. That's how I wired my turn signals because it involved less wire. The green wire is going to end up grounding the the frame anyway.

[Spanner 1]

You,Sir Patrick, are correct...and happy St. Patricks Day on Tues !!

[Patrick]

Erin go Bragh, Spanner.

[j4hfr34k]

i have a similar question. but a little more detailed which wire is for the tail light? coming from fuse boxe the wire is brown and white. but at tail light the wires are green, brown and green with yellow stripe.

[Patrick]

Green is ground. Green and yellow is brake light. Ergo, brown is tail light.

[j4hfr34k]

thanks now my stock tail light works again had been using a round trailer light for tail light

[Spanner 1]

Patrick; 2
Spanner; 1       !