Turn signals and brake light not working

[ed3541]

Hoping someone can help with this lighting problem.
My turn signals and brake light suddenly stopped working. And when I step on the brake, my license plate light goes out also. When this first happened, when I pressed my turn signal and held it in, both green flasher indicators on the instruments flashed.  Now when I press the turn signal and hold it in, they don't do anything. With the Bulb Monitor Unit disconnected, both turn indicators on Instrument panel flash.(So apparently the Flasher relay is working.) I didn't have the front turn signals hooked-up when all this happened.

I'd appreciate any help with this. I did check and clean the ground under the tank. Horn works, headlight works, bike starts and runs.

thanx,
ed

[Laitch]

Hoping someone can help with this lighting problem.

This post from the Technical Library might help.

[ed3541]

OK -  thanx Laitch. I took your advice a little further and replaced the starter with a rebuilt Denso unit that I had on a shelf for years. With new starter installed and rear lights assembly unplugged I got the right turn signal indicator on instrument cluster to blink. But when I hit the left turn signal sometimes I get a buzzing noise from the Flasher relay and sometimes it blinks. When I hooked up the tail-light plug, I got no turn signal activity and my license plate light still goes out when I step on the brake. So it appears I may have a short in the wires going to the rear plug or in the plug itself. I replaced the rear light plug and got the same results. I'd like to have this bike running so I can use it instead of the Triumph Speed Triple I'm riding now. The Speedy is a great bike but it's not practical like my K75.

[The Mighty Gryphon]

Is your tail light stock or do you have any aftermarket visibility "enhancements" like additional brake lights, brake light flashers, or always-on running lights in the turn signals?   Are there any loose wires in the tail light. 

Take the bulbs out of the brake and license plate light and see how the turn signals work.  Put just the license plate bulb in and try the brake.   Then try just the brake light bulb.  Try using new bulbs.

I had a similar problem with the tail light bulb going out when the brake light came on a couple years ago.  I had something connected wrong, but for the life of me, I can't remember what it was.

[ed3541]

Thanx TMG. I think you're idea may be close to the answer. I tried your suggestions and it seemed to help at first - until I put everything back together and still had the same problem. But I'm going to investigate this track further when I have some time.
thanx,
Ed

[ed3541]

Problem solved. It was an intermittent ground. The ground was OK when I was testing with a meter but when the assembly was hooked up in operating position, the ground wire bent enough to cause the intermittent.

Thanx,
Ed

[The Mighty Gryphon]

Good work!  :2thumbup:

Universal Rule #1 of electrical troubleshooting ignore at your peril:

Check and clean all the grounds!!!

I know I often forget it.  Wish someone could tell me why the grounds all go to hell so often when everything else keeps on working and looks so good.   

When I worked on boats I would guess that 3/4 of all the electrical issues were caused by loose or corroded ground connections.  Some of my most embarrassing moments were when I would be stumped on a problem and the yard foreman would ask me what the grounds looked like.

[Bill]

TMG .... anyone who has worked on trailer lighting more than once should know to check the grounds !  Failure to do so results in road side stops and general embarrassment ! :oops:

[johnny]

greetings...

and the popo impounding your donkey trailor...

j o