The wiring diagram for most Kawasaki's tail light circuits is:

BLUE,(sometimes with a red stripe,brake light circuit.
RED, running or tail light circuit.
BLACK, with YELLOW stripe, ground circuit.

I'll give you my electrical trouble shooting guide for shorting and intermittent operation:

The Dreaded Shorting/Intermittent Electrical Problem!

Here is the most basic method I know:

1. Charge your battery if you can.

2. Disconnect the Black lead from the (-) Battery terminal... or Red from the (+) Battery terminal, it does not matter which one.

3. Connect one of the following test setups in series with the Battery terminal and lead:
3.1 A 12 V light bulb,
3.2 A 12 V test light,
3.3 A 12 V test buzzer or,
3.4 A 12 V horn... you get the idea.

4. With the Ignition Switch OFF, go through your harness and wiggle the wires while looking/listening for the test setup to go on/start buzzing.

5.With the Ignition Switch ON, repeat the test except this time the looking/listening for the test setup to go on/stop buzzing.

6. Be prepared to open the Ignition switch and check/test for solder joint failure and or circuit board micro breaks (don't ask how I know this ).

7. Be prepared to pull the wires out of the Head Light to test for failures at or near the grommet.

8. Be prepared to open the harness at or near the Steering Neck for failures. This is where wires tend to exhibit fatigue due to repetitive movement.

9. Be prepared to open the left and right switch gear to search for rust and or broken parts. CAUTION: watch out for flying springs, ball bearings and stuff. Do indoors on White sheet (again don't ask ).

10. Be prepared to follow the heavy gauge wire from the Starter Solenoid (Relay) to the starter for bare ware wire exposure. Especially near bends and grommets.

11. If you can reproduce the fault symptom your are pretty much home free. Be prepare to find and repair/replace any internal wire breaks, insulation break downs, exposed wires, rubber grommet failures, etc. Often, shrink tubing will solve the problem temporarily until something better can be done.

12. I use a very good electrical contact cleaner/preservative called De-oxit made by Caig Labs in San Diego Ca. Their website is caig.com - Home of DeoxIT - CAIG Laboratories, Inc. It can be purchased at Radio Shack and any other electronic supply store. I use it on all of my motorcycle’s electrical connectors , in my home entertainment center’s stereo patch cords and cordless phones charging cradles.

 

Red-Blue is your running light circuit hot.
The pigtail from the turn signal housing itself is blue.

So on the turn signal housing: Blue - Running light, Green - Turn Signal, Black/Yellow - ground.
These will connect in the headlight bucket as:
Blue - Red/Blue
Green - Green (left turn) Gray (right turn)
Black/Yellow - Black/Yellow

 

THis happened on my 1997 VN1500. It happened for a month before we knew where the short was.... it was a stupid wire that was short out on the frame near the gas tank.

 

Good gouge, thanks. I'll get to work now and let you know how it goes.

 

Okay, didn't get very far with this but have some new information. Red wire with Blue stripe is for brake. Just after right handlebar wiring harness plugs in at headlight bucket this Red wire with blue stripe has a ground wire attached which when connected to chassis, blows the tail lamp fuse within a split second. When not attached, fuse doesn't blow. This ground wire has always been there as far as I know so it should be attached I believe. The red wire with blue stripe I also found at the junction box and have perfect continuity from the wiring harness for right handlebar to the junction box. Tried the wiggling wires with 12V bulb in series but didn't find the short. Haven't found the smokin gun yet. Desperately need a wiring diagram. Anyone have one or any more ideas? Gordon 1999 Vulcan Classic

 

Take a close look inside the headlight bucket for a small arc spot. Had one once that had the wire's metal terminal sticking out from a insulator. It would touch once in a while and blow the fuse.

 

Red wire with Blue stripe is for brake. Just after right handlebar wiring harness plugs in at headlight bucket this Red wire with blue stripe has a ground wire attached which when connected to chassis, blows the tail lamp fuse within a split second. When not attached, fuse doesn't blow. This ground wire has always been there as far as I know so it should be attached I believe. The red wire with blue stripe I also found at the junction box and have perfect continuity from the wiring harness for right handlebar to the junction box.

Well... If that red/blue wire is for either the brake or the taillight and it's plugged into a ground wire, it's definitely going to blow a fuse, whether it's "always" been there or not. The question then becomes, why hasn't it blown it before.

It sounds like somewhere in the past someone has jiggered around with the wiring.

When it's disconnected from the ground wire, so all of your lights work including front and rear brake? If so, leave it disconnected.

What was the last thing done to the bike before it started blowing fuses?

 

Rich, The only thing I ever did to it electrically was install kurakryn silver bullet light bar properly on its own circuit with relay but I didn't ground that wire. I have that all disconnected right now and it still blows fuse. It had a cobra light bar on before that I had installed right after I bought it. All my lights work without that ground attached but still looking for something not working with it not attached.

 

Do people still pay for wiring diagrams? Or does anyone know where to find one?

 

OK, this is my best explanation of what happened. I am leaving the ground wire that was spliced to the Red with Blue stripe wire for my front brake disconnected. I don't know why that wire was grounded but when I installed my light bar I noticed that ground was poorly connected so I put a new connector on the wire. My problems started after that. My grounds for the light bar and that ground all attached at right bolt for headlight. I think that ground was attached by someone in error but not actually grounding till I fixed the connector. Weird but right now I've got all my circuits working perfectly. Thanks to all for your tips and expertise. Gordo

 

There's 2 ways to trigger the brake lights... feed 12v to each switch and each switch completes the circuit, or feed 12v to the lamp and each switch provides the ground.

On the 1500/1600, +12v is fed to the switches and the switches in turn supply power to the lamps... so neither of the wires from the brake light switch should be grounded.

Regardless, factory wiring does NOT tie the grounds to the headlight bucket. The grounds connect to a junction connector and a separate (normally larger) wire carries the ground back to the main junction box.

The headlight bucket is a poor source for a ground, as it is connected to the frame by a pair of (hopefully) greasy bearings... and current flow through the bearings can cause electrolysis and corrosion of the bearings.
Yes, the OEM lightbar DOES ground through the bar (doesn't make it a good practice).

The headlight bucket is a GREAT common ground point only if a separate ground wire is run from one of the screws back to the frame.