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wierd wiring

926 views 17 replies 7 participants last post by  tydimig 
#1 ·
So I have a used vtx. Turns out the guy before me had put some clips on the wires right next to the taillamp receptacle all up inside the housing-not visible till you take the whole housing off from underneath by removing the fender. He had clips with male receptacles on the end to plug into to some other extra light I never saw.

Eventually, because the wiseguy never taped the ends off, they kept touching and touching and burned out the wiring and making it unfixable. The result was that the running light and the tail never came on, but the brake light came on when applied. So I bought a new one, housing, wiring, two filament bulb and all figuring that should fix the screw up left behind for me to discover. I put the new tailight in and now, the same problem-only the brake light comes on, no running light!

ANYONE got a clue? I'm am lost. DO I need a new wiring harness, or what???
 
#2 ·
Get a DVOM and a wiring diagram and ohm test each wire from the light assy to the right side cover plugs. You'll need to disconnect them to test ;) That will tell you if you have a bad wire. If not then start checking all your fuses and your grounds also ;)
 
#5 ·
Lights shorted/burned out but fuses still good?? Doesn't normally work that way. As soon as you short, the fuse should pop. The fuses for the taillights/brake/running lights are behind the right side cover and they are encased in a small black rectangular box with a flip-up lid. Most likely, previous owner had a SOMA brake light or auxiliary turn signals or something like that. With the wires running under the fender, you can easily have a short - bare wire touching fender(ground) = short. Two hot wires touching each other shouldn't do a thing.

Other possibility, all the rear wiring has quick-disconnects in a rubber boot also behind the right side cover. Enables one to unplug wires and remove fender easily. Check and make sure that all the wires are plugged in. The factory wiring colors are the same on each side of the quick-disconnet (male/female plugs) so it's easy to check.

If you don't have the ohm meter thing (and I don't either) you should at least try to pick up a test light - they look like an ice pick with a wire coming out the top with an alligator clip at end of wire. Clip to ground/frame and use tip of ice pick to test for hot wire - lights up the handle when circuit is good. This helps find shorts/bad wires.
 
#6 ·
coltergeist

I know what you're talking about-I've done everything you mentioned except checking each wire with a volt meter. The fuses were fine before I started this thread. I have a volt meter and need to check it next time I get the chance. I'm just trying to see what others think at this point.

I really believe there might be a broken connection in the old wiring harness before I get to the connection of the light under the side panel on the right-the whole new tailight seems to be fine and ought to be since it's new out of the box, but again, I need to go back and check with the probes on the volt meter.
 
#7 ·
new thought

If the wire in the harness is broken somewhere, instead of replacing it, or them, couldn't I run new wires, appropriately connected and grounded with zip ties to frame and all back to the light? In theory?
 
#8 ·
If the wire in the harness is broken somewhere, instead of replacing it, or them, couldn't I run new wires, appropriately connected and grounded with zip ties to frame and all back to the light? In theory?
Yes, but it's unlikely you'll find that you have to replace the harness. It's more likely you'll find a wire that is cut.

1. Check for power at the wire where it goes into the tail light assembly.
2. If none then check for power on the tail light wire under the side cover.
3. If you have power there then the problem is between the side cover and the tail light. If not, keep back-tracing the tail light wire until you find the issue.

Odds are you will find something is disconnected, pinched, cut, or worn through. All are easy enough to fix with a butt splice and some heat shrink. ;)
 
#9 ·
What birdiemn said.

Find the light at the taillight that powers the particular problem light. If you have power there, then the problem is in the taillight assembly. If you have no power at the taillight, but have power at the connection under the side cover, then your problem is a break in the wire between the side cover and the taillight. It is not uncommon for the soft metal clamps under the rear fender to abrade the taillight wires to the point where they will short out. Been there, done that.
 
#10 ·
latest new development

So, the running light wasn't working, but I figured I could take a short ride during the day with out any problems. Now, none of the turn, brake, or running lights on the new tailight are functioning, and the 10 amp fuse is blown. Is there are short in the wire somewhere on the harness?:(
 
#11 ·
Yes, you probably have a short. Time to do some investigating, as mentioned above. Tracking an electrical problem can be a PITA, but it is doable.

I would recommend removing the rear wheel so you can see the wire run and get at it easily. But I got huge hands, so when I do any electrical work in the rear I have to remove the rear wheel.
 
#12 ·
The electrical wiring diagram can be found in the shop manual.
At the bottom right side of the page is a listing of what is powered
by each fuse.

The taillight fuse gives power to the speedo lighting and
the front running marker (amber lights).

The brakelight has a separate fuse from the taillight function,
but the horn and the turn signals are also on the brakelight fuse.

It helps to know the colors of the wiring associated with each circuit,
but if you don't, you can trace them from the shop manual.

Often, if you do not have blown fuses, the problems can be
due to unconnected wires in the main bundle under the right painted
sidecover.

Sometimes, problems in the rear wiring can be due to tires rubbing on
the wiring under the fender, especially if wider than stock tire is
mounted on the rear, or shorter than stock shocks are mounted on rear.
wiring under the fender is supposed to be run along the inner fender support, but once in a while it is pinched by the fender and cut by it,
or rubs on the tire.

Taillight is brown wire.
Brakelight is green with yellow stripe.
Ground is solid green.
Left turn is orange
right turn is lightblue.
 
#13 ·
Short bus rider still needs help

So it seems that the short is up in the harness somewhere. Any suggestions about how to fix it ???

The tailight assembly and wires are all new, and the connections seem to be ok under the sidecover on the right, but the 10m amp fuse keeps blowing. I'm guessing that the short is in the harness? How do I find it? Do I need to unwrap all the electrical tape??!

I'm a little nervous to try with out any feeback; can't afford to take it in, can't afford to mess it up even worse, either.
 
#14 ·
So it seems that the short is up in the harness somewhere. Any suggestions about how to fix it ???

The tailight assembly and wires are all new, and the connections seem to be ok under the sidecover on the right, but the 10m amp fuse keeps blowing. I'm guessing that the short is in the harness? How do I find it? Do I need to unwrap all the electrical tape??!

I'm a little nervous to try with out any feeback; can't afford to take it in, can't afford to mess it up even worse, either.
Have you verified circuit continuity in all of the wires running under the fender?
 
#17 ·
The way to determine whether the short is under the rear fender
or elsewhere is to replace all the bad fuses and then disconnect all
of the wiring that goes to the rear.
Then turn on the motorcycle and see if the fuse still blows.

Just because the wiring in the rear fender is new does not mean
that it was installed properly and will not cause a fuse to blow.
 
#18 ·
good thinking

Coyote7864

You're right. Wish I had read your post or thought of this before I tore into it today; could of saved myself a lot of effort, as well as the new pitfalls.

I had bought awhile back real cheap, a used wiring harness and am now in the process of making it work on my bike. The only snag I'm running into now, is that it looks like it came from an R model, but mine is a C.

This works out for me though, as a bonus, since I put on an R tank last August and have the speedo and dash for it, that will now fit the connections without having to cut or splice anything. The only problem I seem to be running into now is that there are a few connections still different between the two harnesses and trying to get the new one to work. It seems that the radiator end might all be different - I dunno.

BUT, the tailight assembly is working just fine now gentlemen, thank you very much. It seems I'm onto new possible headaches now. I am not stupid, but I'm not a mechanic either. Stayed tuned and see if Frankenbike will rise....:?
 
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