Hi all.  New to the brick world and wanting some help.  In the late winter I bought an 85 K100RT.  I had driven two hours to get it and it was pouring rain while I was checking it out.  The bike was started and then we loaded it up and I got on my way as fast as I could.  The one thing I did not check were the turn signals.  I would have bought the bike whether they worked or not.

I have absolutely no signal light action whatsoever, using either left or right or the hazard switches.  I replaced the fuse, cleaned the contacts under the tank and have even tried a different right hand turn signal switch.  Is the final candidate in the process of elimination the starter?  The bike starts very easily and the starter does not seem to be showing any issues.

Thanks, Andrew

The flasher relay is powered by two fuses that need to be checked. Fuse 7 is switched power and Fuse 3 is unswitched power. (The latter is used to power the hazard signals when the bike is turned off. But the hazards can only be turned on when the ignition is on. This is so you can have the hazards running while the bike is turned off but some idiot walking by can't turn them on and drain your battery without the key.)

At least in my experience, a bad starter ground will cause weird behavior, not complete failure, of the turn signals so my GUESS would be that your flasher relay might be kaput.

The relay was something I thought might be the problem.  Is there any way to test it or even bypass it to see if it is causing the problem?

Thanks for your help with this.

Andrew

I recently had my left turn signal go out and decided to open the signal up (on the bars) and noticed a loose wire that was no longer in place where it had been soldered in. Holding it in place enabled the signal to work. A lucky and very easy fix in my case , I'm guessing maybe the zip tie on the bars was too tight along with all the years . And really hoping this kind of loose connection isn't a common problem with theses bikes , as any other loose connection could be a real pain to find !

Here's how to run some tests of the wiring to and from the flasher relay. There's no easy way to test the relay itself other than trying it on another bike.

The flasher relay is located in the left rear corner of the relay box behind the fuse block and held on by two 8mm hex head screws. Its casing is green on early flasher relays and black on later ones.

At the flasher relay connector:

When you depress the right turn signal button there should be continuity between the brown wire and the blue/yellow wire.

When you depress the left turn signal button there should be continuity between the brown wire and the blue/brown wire.

When you put 12V+ to the blue/black wire the right turn signals should illuminate.

When you put 12V+ to the blue/red wire the left turn signals should illuminate.

Good info Duck.

Thanks.

Thanks Duck.  I have a mechanic buddy who will give me a hand with this now but of course he is out of town until next weekend.  When I get this sussed I will tell you all how this has turned out.

Cheers, Andrew

Progress (or lack there of) report:

I checked the light bulbs - all good
I changed out both 15a fuses to new ones
I replaced the relay with a new one
I replaced the right turn signal switch since it didn't click and the left one did
I hit all the contacts that I could find with contact cleaner

Still no turn signals or hazards.  Absolutely nothing.

I would greatly appreciate any guidance on where to turn to next.  My mechanic buddy is back in town so I will be trailering the bike over to him in the next couple of days.

Did you run the checks that the Duck suggested?  They are important in finding where exactly your problem is.  And will locate it much more accurately than changing parts.

Will do.  My mechanic buddy will be away longer than I had hoped.   I will muddle through as best I can.  Testing electrical is definitely new territory for me.  I truly appreciate all the help that this forum has to offer.

Okay so I ventured into that new territory and here are the results.  I tested for continuity per the instructions provided by Duck and both are good.  Same also for supplying power to both signal lights. Family duties arrived and so that was as far as I got.  

Would it be the case that power is not getting to the relay?  That's what I wanted to test for before getting called away.  Back to it tomorrow night.

Red/white to the flasher relay is unswitched 12V from Fuse 3.

Green/brown to the relay is swtiched 12V from Fuse 7.

I finally got this issue resolved this past weekend.  At the end of the day it turned out to be fairly simple and the whole process educated me a great deal with regard to some of the systems hiding inside the K.  

My mechanic buddy was able to make it over and he re-tested a bunch of the stuff outlined above.  He was scratching his head and then checked continuity on the fuse.  There wasn't any so we popped them all and sanded all the tangs. Back into the holder and everything was tickety-boo.  I had replaced the fuses with the new ones that were still in the sealed plastic package that got shipped with the bike and I had also sprayed contact cleaner into the fuse holder but that wasn't enough.

My own mechanical knowledge stopped expanding when I left the farm in the early 80's and most of the things that I did any sort of work on was quite a bit older than that.  The K at 33 years old is decidedly modern compared to anything I ever worked on.

I have no regrets at all about buying both new and used parts in trying to solve this issue either.  The relay for example started off at over $300 CDN and the one I eventually purchased was about half that.

Thank you all for the much appreciated assistance.

I replace those blade fuses when I get another bike because they have a habit of going open circuit with a bit of age and can be very erratic as to working or not.

Thanks all for the info. I was out for a ride yesterday and lost the turn signals and horn. I visually checked the fuses and they looked OK. After finding this thread, I tried Woodie's cure and replaced the fuses. Problem solved!

Glad it was an easy fix for you Woodro!  Some day I hope to get out your way there on the Rock.  I can't imagine a better machine for Newfoundland than the K.

Cheers, Andrew