Tail light help!!

[Muscle racer]

last week I lost my tail light while riding, so I bought another online to replace it. yesterday I spent 2 hrs trying to hook it up, then gave in.

The original tail light had 2 wires, low beam, high beam and the ground hook up. The new one I bought has 3 wires, Im sure ground is 1 of the 3 (as shown in the pic). I tried every type of wire combination, but they all blew my fuse.

A few times, I hooked up the 2 wires, then when I pressed the brake, the light would turn off, instead of becoming brighter. Someone on here suggested I use a 12v source to check the wires, but the bike itself is all I have.

I wanna ride so bad. Pls help me. thanks

[sgtslag]

Go to a DIY store, or Radio Shack, and purchase a $5-$10 Digital Volt Meter, or a continuity test lamp.

Continuity Light:
With the test lamp, start the bike, then connect the test lamp between the bike's black wire, and one of the the other two:  if it lights up, this is the tail light wire, which has power as long as the key is on; if it only lights up when the brake lever is depressed, then it is the brake light wire.  Follow the wiring listed below, with your light:  black wire to ground wire, then determine which wire, red or yellow on the new light, is the tail light and brake light, and wire accordingly.

DVM:
Set the meter for 0-20 VDC Range.  Connect the black/negative lead to the bike's chassis.  Connect the red/positive lead to any of the three wires, with the bike running.

If the wire shows 12 volts, or more, then it is your tail light wire, which is powered on, whenever the key is turned on.

If the wire has no power, press either of the brake levers, and see if it gets 12 volts, or more, when the switch is depressed:  if it does, then this is the brake positive lead, which activates your brake light; if it still does not get power to it, then it is the ground lead for the lights.  Verify the ground lead by switching your DVM to Ohms, and touch one lead to the wire lead which had no voltage on it, and the other to the chassis:  you should read less than five Ohms.

To test the wires on the light assembly, you will need your DVM again.  The black lead should be the ground/negative lead, but you will need to test it, to verify this:  connect the black DVM (set to Ohms) lead to the black wire, then connect the red lead to the red, and then the yellow, wires.  You should get a reading higher than two Ohms, on each, if the black wire is the ground lead.

Next up, you need to determine which lead is the tail light, and which is the brake light.  If the black lead is the ground/negative lead (determined in the previous steps), connect it to the chassis, or black lead on the bike.  Then connect the yellow wire to the tail light wire, and see how bright it is:  the tail light is around 7.5 Watts, and relatively dim.  Then connect the red wire to the the brake wire, and press the brake lever:  the brake filament is around 23-27 Watts, and it is much brighter than the tail light.  Once you have determined the correct connections, either solder them, and cover with tape, or use a good crimp-on connector, and tool, to secure the wires, cover them in electrical tape, if the metal connectors are exposed, then mount it, and ride.

If you are blowing any fuses, it is because you are connecting one of the positive, power feed wires to the ground/negative lead/chassis.  Let us know how it turns out.  Cheers!

[shinyribs]

Muscleracer,if those colors are not correct for the factory harness,then a pretty good chance that black is your ground.Just look and see which of those three wires is fastened to the metal base of the light bulb holder itself.That will be your ground.Try the other two and if it doesnt function properly(ie:tail and stop work in reverse operation)swap 'em and you should be good.

That green wire you are holding should be your ground on your bike.Honda used dark green as their ground so that part should be easy enough to figure out.

[Piute]

 I agree there Chrome ribs

    This helped with my trailer;
 found an aftermarket wiring guide and this is what it says:

- Black wire on taillight to green wire [-ve ground]
- Yellow wire on taillight to Brown wire [running lamp circuit]
- Red wire on taillight to Green/Yellow striped wire [brake circuit]
- Turn switch on; test brake light function before riding, while bike is stationary; if brake light remains ON (bright) and dims when brakes are applied, swap red and yellow wire connections; check again for correct brakelight function

[Muscleracer]

Hey guys. Thanks for the response. I split the black wire and the ground on the bike and twisted them up. I hooked up the yellow and red and the light stays on. I switched them out and it still just stays on. When I press the brakes, it doesnt change. It just stays on the whole time.

What did I do wrong.

Tks

[Piute]

this MAY BE CRAZY BUT you check the bulb to be sure it has
2 silver spots on bottom double aliment

[TOOLS1]

What color wires are, you connecting to on the bike?
TOOLS

[shinyribs]

Double check that your brake light switch is not stuck.Its not that hard to accidentally to hit the one on the foot pedal.Just a thought.Of course,the tail light burns anytime the ign. sw. is in the "on" or "park" position.ALso make sure the switch IS on,or the brake light will work at all.They are now like autos where the brake lights are "hot" all of the time.

[Muscleracer]

So here's an update.

I took the tail light apart, and found that the ground is yellow and not the black wire. So I attached it to the screw and hooked the tail light up and it works.  I'm back on the road.

Thanks for the help.

[shinyribs]

Awesome!!!Now go burn it up!!!...the road...not the bike,of course