Modern Vespa

So, the horn quit working a week or so ago, I didn't think much about it at the time. Then the next week it wouldn't start. I pulled the fuses that are in the left panel of the dash, and they were quite corroded with a film, so I replaced them. It fired up, but still no horn. The next day, it wouldn't start, so I pulled the fuses and they were blown. Replaced them, disconected the wires from the horn and it seems to be starting now. Could the horn be causing some kind of short?
Thanks

Anybody?

repeatedly blowing fuses almost always means that you have an uninsulated wire coming into contact with metal bodywork and shorting out. if disconnecting the horn has solved your problem that indicates that most likely the wiring to the horn is damaged. check it out and let us know.

Will do! Thanks for your advice. Does anyone know how to check the horn? If I used a voltohm meter, should it pass?

i've reached the limits of my 'expertise' when it comes to electrics so the only further advice i'll offer here is that you might want to edit the title of this post so it's more specific to your problem. if you bait the trap properly you'll find you attract loads of experts

Umm, ok. I might just start a new post if this one doesn't yield results this week. I'm not sure how to edit the title. I see your kind responses all over this forum. If you haven't any advice on this issue, I don't know who would be more informed. Tell everyone in England I said hi! Thanks again.

Here's a thread that might be heplful:

Best way to track down a shorted wire

you can find the service manuals here:
http://www.wotmeworry.org.uk/manuals/ET4/

(Basically your best chance is to visually inspect the wiring from the horn back looking for pinched or bare wires; you can also clean up any corroded contacts & give them a coating of dielectric grease.)
Good luck with it!


Regards
Harvey

Thanks! Should I clean the contacts with spray electronics cleaner?

i've taken the liberty of editing your post title for you in hopes of attracting some more specific answers ... Harvey has already given you a link to a useful thread on the topic.

I would try some fine steel (or brass) wool (don't overdo it), then a blast of cleaner ( try a twist on a toothpick, etc. for the female plug).

Good luck with it!

Regards
Harvey

You and Harvey rock! Please, take any liberties you deem necessary! i read his link and am off with a flashlight and meter!

Jim C recommended a fibreglass pencil to me for cleaning contacts, which turned out to be excellent for the job. Not abrasive enough to damage the contacts, but they fair shine afterwards. Nice and cheap too. Just be careful not to get any skelves: gloves might be a good idea.

After checking Google, Wikipedia, the American Heritage Dictionary, and even the Oxford English Dictionary, my American dialect-burdened self is no closer to understanding "skelves."

Not heard it before either - but it is quite a good word for the horrible tiny bits of fibreglass that can get caught invisibly in your hands and are excruciatingly irritating.

Try the singular: "skelf".

Be careful with what type of contact cleaner you use. A lot of the contact cleaners available on the market leave a white or green "film" which can cause problems later on, especially if the scoot is stored outdoors. I would recommend using a product made by Caig Laboratories called DeoxIT.

Here's a link- http://store.caig.com/s.nl/sc.2/category.188/.f

I work in the broadcast electronics industry and this is the best contact cleaner EVER!

You should get the small spray can of DeoxIT D5 (Caig item #D5MS-15), Deoxit Shield S5 (Caig item #S5MS-15), and some small nylon brushes (Caig item #AB-25).

Spray a small amount (you don't need very much) of DeoxIT D5 on the contacts and let it sit for 2-5 mins then scrub with the brush. This process may need to be repeated depending on the amount of corrosion.

Once the contacts are clean apply a small amount of DeoxIT shield S5 and allow it to dry. This will help prevent corrosion, or at least slow it down.

P.S. I do not work for Caig. I just love their products.

Jeez, I'm dumb sometimes.  I just assumed the singular was "skelve."  Thanks for clearing that up.

Just so happens the horn on my fly 125 has packed up & the wire loom is the same as the et4 . Yours won't start when fuse blows because that fuse has brake lights and starter circuit on it .
Mine will work off & on working sometimes and the next dead , holding the horn button in and riding on a bumpy road will make the horn beep .
I have removed and cleaned / tested the horn botton with a meter set to the sound setting , Push horn button and beep sounds on tester .
With the fly you have to remove most of the panels to get at the horn

I will check live feed to button then live feed from button down to horn which is then earthed to frame .

The fault might be as simple as the wire hanging off the horn .
but worst case would be new wire run to button or horn .

Or wire up a nice loud air horn

Well, I'll get that cleaner. I looked the wiring over, took the front panel off and disconnected the 2 leads to the horn. the fuse still blows when i try to honk the thing, so maybe it's the switch. i might just try to get a replacement so that if i have to take that steering column apart i'll have the replacement part.
no splinters yet!!!

Just a precaution on the fiber glass pencil brush, I use it myself and it does work fine...however the fiber glass does wear down to a fine powder and as report earlier can irritate your skin.

More important do not go anywhere near your eyes...for obvious reasons.

I had a similar problem with my GT200 a while back. The culprit was a wire that had become pinched between a plastic headset panel and a metal piece of the body just behind the switch. It had worn a tiny bit of sheathing off the wire, thus causing a short. It was such a small area, it took me three inspections to find it.

I fixed it with a few wraps of electrical tape.

If your other options don't work out give the wire another close inspection or two.

Good Luck.

I finally got this fixed. It turned out to be a short where the mirror screwed into the column and pinched a the wire. The starter and horn were indeed on the same fuse, so you could press the horn button while running and it would blow. Of course once you turned the scooter off you were screwed. It's back now and that horn is massive

Glad things worked out and thanks to everyone who recommend links where those who are "electronics chanllenged" (me!) I can read up on this so I don't burn out my system. I've saved this away in my Electronic Stuff folder...thanks! Many thumbs up!