The wire harness for this bike has been chopped and spliced for a few rounds. I managed to get the harness to what I thought was 100%, however here is the problem:

Problem:

With key in the ignition, the rear brake light is constantly illuminated.

And when I select the right or left rear flashers, from the handle bar switch, both right and left signal indicators have low illumination, if any at all and the rear tail light pulsates.

Here is a link to a video of it happening:

• Video of problem
  

My theory:

Now all the lines match, strand for stand. I retraced the lines for continuous match of color code for a second time. There are two brown lines, I noticed that Yamaha designated on this bike. The dark brown lines belongs to one of the turn signals; Dark green is the other signal color. The lighter brown, which I'll identify as TAN, is the power line that delivers power throughout the bike. Now I thought that the brown and tan lines were simply misconnected, but they do not appear to be this way. The bike starts easily, and shuts off with both the key and emergency kill switch.

But what also doesn't currently work is the horn. I was able to test it with a 12 volt direct connection, and i know it it works.

Now the wire harness within the headlight enclosure are just "plug and play." So there doesn't seem to be a mix up at all going on up there.

Here is a link to the wire diagram that I'm currently using. Please discard my original tracing colors.

• Wiring Diagram
  

So, any ideas?

And here are some of the picture of the open wire harness.

Hiya,

For the brakelight check the front and rear switches which may be broken or out of adjustment, causing the light to come on all the time. Normal that it dims with the indicators on without the engine running. Are the rear indicators connected as thety weren't working with the front?

For the horn, check that the wiring is getting power with a voltmeter. Might be a dirty connector or in the switch itself.

Hope that helps,

Gordo

I must have popped the fuse... I lost all power now to bike.

I just found a used wire harness on ebay, listed as in good shape for a '79 DT250. According the manual, this should definitely work.

I'm still gonna be working on the one that is currently on the bike. I'll let you know where I end up. Thanks for the advice.