Took the bike in for it's MOT this morning (pillion footrests attached, just in case) and wandered off for a fried breakfast whilst they sorted it (any excuse...).
Came back after 30 minutes. "Sorry sir, it failed. The horn is not working".
Now, I've had problems with this about 6 months ago, when the accessory power socket corroded, shorted and took out the 15 amp fuse which it shares with the digital clock on the dash and the horn. I solved the problem then by tracing the wire from the accessory socket back to a connector block under the right hand rear fairing panel and disconnected it. I taped up the connector on the bike to stop moisture getting in, replaced the fuse and we were back in business.
"No problem", says I to the MOT man, "It will be the fuse and I have a spare." I went out to fettle the problem and had a look at the clock on the dash. Strange, it's working so it doesn't look like the fuse has blown. Ignition on, I press the horn button and it makes a half hearted crackling noise as though there is a loose connection somehere. I disconnected the horn cable at the connector block just below the horn and the terminals seemed to be clean. I re-connected it and tried again. At that point the MOT inspector starts wandering over to the bike (which is parked on the street outside the shop) and asks if I've fixed it. I press the button and it emits a decent kind of a parp, so the guy says "that's good enough for me" and turns to go back to the shop to get my certificate. I try a couple more times when he's out of sight again and the horn is once more dead but the clock is still running....
This evening, I've taken off the rear fairing panel to expose the redundant connector block for the accessory socket. Peeling off the tape, I discover that it's dry, but full of green corrosion dust. One of the wires coming out of the connector block has snapped from the terminal in the plug, but is not shorting on any metal surface. I cut off the connector from the other wire and taped up the ends of the wires so that they cannot short out. Tried the horn again, but it's dead as a dead thing. Check and replace the 15 amp fuses, but no joy. When I turn on the ignition now, the clock is working fine. As soon as I press the horn button, the digital clock now slowly fades and resets itself. If I turn off the ignition again, the clock comes back to life (at 1:00) after a few seconds.
So, what's the problem? I'm coming round to the idea that the accessory socket problem was a red herring and it's actually the horn button that's buggered - but then if that is shorting, why is the horn not sounding? Anyone out there with more clue than me (that's frankly most of you
) care to suggest causes/solutions?Cheers,
Paul
