Weak horn circuit

[Zook1100]

I can look at a physically work or broken part, say "well THERE'S your problem," and figure out how to replace it pretty easily. But electrical? Stumps me more often than not. Too theoretical for my "hands-on" brain.

So, '82 GS1100L. I'm working out a bunch of minor issues on this mechanically solid $350 bike. Among them, the horn. It barely made any noise at all. No problem, I said - I have a perfectly good compact air horn on my CB750 that I want to swap over to the GS anyway. So I did that. But the problem isn't the horn itself. I can hear the air horn compressor spinning a little, but not enough to move air through the horn effectively. Also, the stock horn I pulled off the GS now works perfectly on my CB750 (can't sell it without a working horn!) So the problem is elsewhere. What might cause the power to be weak, but not a completely open circuit?

Another issue, which may or may not be related, is my turn signals. They are small aftermarket replacements. I have them all wired in now, and they turn on and off appropriately - but they don't blink. Could this be related to the horn issue, since they share the same controls?

[duaneage]

Bad ground at the horn button. Can be caused by black painted handlebars too. There is a black wire and a colored wire on the horn. Using a voltmeter find out which one is +12 and connect a grounded wire to the other terminal. If the horn sounds loud it's either the horn button, the ground for the control on the handlebar, or the wires between have a bad connector.

[Redman]

I can look at a physically work or broken part, say "well THERE'S your problem," and figure out how to replace it pretty easily. But electrical? Stumps me more often than not. Too theoretical for my "hands-on" brain.
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To "look" at electrical problems you need a volt meter.

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[Zook1100]

The answer turned out to be a great big DUH. I was inspired to reverse the polarity of the power being fed to the horn during my lunch break at work today. So I went out into the parking lot and did it. My surprise when I test blew a now fully functional air horn must have been comparable to that of my co-workers. Which means the original horn was wired up backwards, too, given its miraculous recovery once installed on my Honda.

I love it when a problem is so simple. But in a way I also hate it, because I feel dumb for overlooking it for so long.