Tail Light Problem

Hi All,

I have a tail light problem on my KZ550c (Ltd). Electrical is my weakest point so hoping for some insight!

Brake light works. Tail Light does not. But when I put my meter on the contacts I get a reading - I believe I am reading 24v DC. Changed bulb and fuse - same behaviour. Any idea why I wouldn't get the light on when I have voltage there?

Thanks!
Dave.

Here's a link (from KZR's Filebase under KZ Information) to 1980 KZ550 where wiring diagram may be downloaded (viewed).

download wiring diagram

Note the three wires from rear bulb, being one red, one blue and one black/yellow.

The black/yellow is ground.

Red and blue are for rear bulb's tail light filament and brake light filament. But I don't know which is which. Would wild guess red to be for brake.

Anyhow, when bike headlight is burning, either red wire or blue wire (one or the other) should then be providing 12 volts to rear bulb's tail light filament.

When either brake is applied, either red wire or blue wire should then be providing 12 volts to rear bulb's brake light filament. Reportedly functional brake light indicates either red or blue is indeed providing 12 volts to a good rear bulb filament and that the black/yellow ground wire is okay.

The black/yellow wire must be providing a good ground connection for either tail light or brake light to function.

The voltage is d.c., same as the battery.

Good Luck!

If the bike is setup similar to my 79' 650 here is what I would do.

Flip up the seat and remover the plastic tail piece/fender. Under it you should see a grommet through your rear fender with a wire harness running through it. It should have 3 wires, one black and two others. The black is your return to battery. Disconnect this harness at the junction near the grommet and test your your voltages going back to the bike. One lead should be hot when the taillights on and the other should go hot when you hit the brake..

If these test good remove the bulb from your taillight and check for a short between any 2 wires in the harness. With no bulb they should be open. If you have a short you either have a bad harness or socket.

This should get you started...


On my 79' I had all types of electrical problems and it ended up being the main junctions under the tank had literally rotted away over time causing random shorts and opens...



OOpppss , typed this while Patton posted...

So more of the same.....

As stated, on most Kawasaki's RED is the running or tail light circuit,BLUE(sometimes with a red stripe) is the brake light circuit, and BLACK with YELLOW stripe is the ground circuit.

You should be reading battery voltage(12-13 volts)at the socket.

OK thanks everyone!

Got it fixed. I was reading voltage at the rear, but was not reading my meter properly! I was barely getting any voltage. Checked wires and found a bad connector.

Dave.