help needed with Rocket III

[holtdentalcare]

Hey, I am hoping someone has a suggestion for the problem I am having. My tail light and the light above the license plate are not working. The brake light is working. Thanks for helping.

[Wimpy]

I'm assuming the headlight is working or the bike wouldn't start, so chances are the tail light bulb is bad. There are two filaments in the bulb, one for the tail light and one for the brake light. Every gas station has them. I believe the number is 1137.

[holtdentalcare]

yea i did that and the problem has stayed the same.

[Ugarte]

I had the same problem. Pull the bulb assembly out and take a close look at the wiring. One of my wires had been rubbed raw and was shorting out. I taped over it and its been fine ever since.

[Diego]

Originally Posted by Wimpy

I'm assuming the headlight is working or the bike wouldn't start...

Well, you know what they happens when you assume. It is entirely possible for the headlamp to be burnt out or unplugged, and yet for the bike to start anyway. There is no current sensor or interlock to prevent it.

The myth got started when someone noticed that the lights share the fuse and relay of the starter circuit, and then added up two plus two to make six. While it's true that the lights will not work if the fuse is blown or the relay is out of circuit, the reverse is not true. Functioning lights are not necessary for the starter to work. Just the opposite, in fact--the headlights are actually off while the starter is cranking! The only reason the headlamp circuit passes through the starter relay is because that's the easiest way to kill current to the bulb when you press the start button, leaving all the battery's power available to the starter motor.

Since new bulbs didn't fix the problem in this case, I endorse Ugarte's advice. Check for damaged wiring, or maybe the possibility of a connector being loose. The wire feeding these lights should be a yellow one. It runs back to fuse 10, which you may also want to check if you haven't already.

(Interesting side note: the tail light and license plate bulbs do have one thing in common with the headlights, albeit remotely. The same circuit, via a different path, also feeds the small bulbs in the headlight assemblies...the ones Triumph calls "position light" bulbs. If you find fuse 10 blown, but the wiring back to the tail light and license light seems OK, then you might want to start checking frontwards for a shorted wire as well.)

[TRIIICK]

Originally Posted by Diego

Well, you know the saying about what happens when you assume. It is entirely possible for the headlamp to be burnt out or unplugged, and yet for the bike to start anyway.

Thanks for putting that myth to rest, every long distance ride i've carried extra bulbs. Now that i've seen the light i can put that worry behind me..

[Diego]

Enlightenment is our goal....

[holtdentalcare]

Checked bulbs and they are okay. Yes the tail light the light above the license plate and the small lights in the headlights are out. The fuse seems to be okay as well. Checked wiring for any areas that may have rubbed away and things look good. Now I did have the ignition replaced about a month ago because it had a short. Would the ignition have anything to do with this problem? Is there any other areas I need to be checking?

[Diego]

The ignition should have no direct effect on that lighting circuit, although there could have been a connector not reconnected during that work, or a wire broken internally in the wiring loom, or a similar fault.

You say the fuse "seems" to be OK. Did you substitute it with a good one, or actually check the continuity with an ohmmeter? If so, the next step in troubleshooting would be to see if you have 12 volts present at the hot side of the socket for fuse 10 when the ignition switch is turned on.