No beep beep

1981 KZ1000, I'm trying to figure out why my horns aren't working. Of course the first step was to test the horns on a battery, but they work fine. So I pulled out the wiring diagram... Brown wire brings the voltage to the horns, and I measured +12 to each of them. Taking another wire to the second terminal of the horns, I also get them to beep. So that leaves the switch, and this is where I'm running into problems...

The wiring diagram shows the horn switch connected by a black/yellow wire which appears to connect to chassis ground, and a black/white wire which leads to the horn switch. I pulled the harness off the bike for the left hand switch cluster, and I found these two wires come out in a 9-pin connector. However putting a meter across those two wires, I do not get a short when I hit the horn switch. I actually have a second switch cluster (the original from the bike) and it also does not show a short when I hit the horn. So either I'm not looking at the correct wires or both of the horn switches appear to be broken?

Now I'm stumped... I've removed all the screws I can see inside and outside the switch assembly, but I cannot figure out how to remove the blinker switch so that I can see the horn switch. The blinker switch looks like it is just sitting in a slot, and it wiggles around freely on both assemblies, but I can't seem to get it to move up or down. There is one bit I can't remove -- on the bottom of the switch assembly there is what looks like a button-head allan bolt, except the hole is completely round, so I don't know if that's actually a thing that needs removed or if it's just some kind of dummy bolt head or what. Anyway, I'm hoping someone has disassembled these before and can give me a clue how to get down to the horn switch? Or perhaps tell me if I am testing for a short on the right pair of wires?

Thanks.

Did you do anything to the bike? It just stopped?

The horn gets it's ground through the handlebars.
Steve

The entire bike was stripped and rebuilt from a non-running condition, so there's no telling if it ever worked. The replacement switch cluster came from ebay, so again I can't say...

However I've been playing with it some more, digging into the non-obvious aspects now that I eliminated all other ideas, and I found something. If you look on the bottom side of the cluster there is a hole under the horn switch where you can see things moving as you push the button. So I did what any geek would do -- I stuck a screwdriver in it -- and my meter lit up showing a short! I have some tiny files so I got one in there thinking maybe th moving parts are contacts that needed cleaning, and this does in fact seem to be the case. I don't want to get too aggressive with the file but it seems like the horn switch is doing something now, although not reliably. Is there something I should try squirting in the hole, or do I need to get some contact cleaner and see if that clears things up?

The slide switch is held down by the screw holding the switch arm down.
Steve

I've never had mine fully apart....but I do know that when I got my new bars I forgot to scrape the paint off...oops...lesson learned. Sounds like you got it...just clean up everything.

OK I completely missed that screw on the switch... but no worries. I spent a little more time cleaning the contacts and now they seem to be 100% reliable, making contact every time and at every angle. Will throw it back on the bike tomorrow and see if I can get a beep.

Thanks for the info about the handlebar ground. If I still have trouble with it, I'll know where to check next.

If you have painted or anodised bars you need to clean off the paint so when the switch is mounted the switch case will ground through the bars. Make sure the switch case where it contacts the bars is not oxidised also. If you have a look at the case recess where the bars would sit there should be a little knob standing proud. This is so when the case is screwed tight onto the bars the little knob on the case is getting good ground.

Warren3200gt wrote:

If you have a look at the case recess where the bars would sit there should be a little knob standing proud. This is so when the case is screwed tight onto the bars the little knob on the case is getting good ground.

This little knob is to prevent turning around the switch cases,(plastic), on the L/R side of the handle bar. To get a good ground to the main frame and battery negative you have a blanc metal to metal surface connection.
On a plastic switch housing is an extra little connector plate to get in touch with the handle bar metal/ground negative.

Just an update to say the problem is solved -- getting those contacts cleaned up was all I needed and now the horns are working. Also of note, on an '81 the switches do NOT ground through the handlebars. There is actually a return ground line in the wiring harness (black/yellow), and I tested the horns before I even put the switch cluster back on the bike.

Anyway thanks for all the help, glad it turned out to be a fairly simple repair. Now I can get back to working on the carbs again...