Brake Light always on - Vespa Grande Super Deluxe

Hello, Ive had trouble starting my grande recently, just takes more speed or a downhill pedal to get it going, and coincidentally the brake light seems "stuck" because it is always on, even when I switch the headlight off and dont brake. I read that electrical shorts and problems can cause rough starts, but I looked and all of the wiring from the brakes to the brake light seems intact.... Not sure how to fix this. Rewire the whole brake light?

Re: Brake Light always on - Vespa Grande Super Deluxe

one or both of your brake switches isn't making contact.

installed, with the lever released, you should have continuity between the pins on the switch.

i remove the switches, put in a baggie of pb blaster, and work the plunger until no bubbles come out, cleans the contacts nicely.

jumper across the switch contacts with the ped running to see which causes the brake light to go out, that's the open contacts.

Re: Brake Light always on - Vespa Grande Super Deluxe

Thanks a lot, I used a dollar store lime rust remover and soaked the brake switches after testing them with a multimeter and not finding continuity in either. Now one works great, and getting another one shipped to me along with a kickstand this week. The ped starts much easier now too and idles with a purr!

Re: Brake Light always on - Vespa Grande Super Deluxe

Jimbo Grand Daddy /

The vespa switches are opposite of Puch switches. The brake light is part of the ignition ground. You should have NO continuity on the switches when pulling the brake lever. This is referred to as a normally open switch. By contrast, a Puch brake light switch WILL have continuity when pulling the lever, as the brake light is powered by a separate coil. This is referred to as a normally closed switch. The style of wiring vespa uses for the brake light circuit will cause he engine to kill when applying brakes because the ignition ground is routed through the brake light filament when the brake lever is pulled.

My refommendation: remove both switches from the brake levers and check for continuity when at rest, then when depressing the plunger of the switch. I suspect one of the switches may be normally closed instead of normally open.

Re: Brake Light always on - Vespa Grande Super Deluxe

Thanks for the clarification Jimbo, you are right about one switch being normally closed. After I tested it with the multimeter and tried cleaning it, it was still normally closed, so I removed the switch and simply rubber-banded the two brakelight wires together temporarily for the back brake. Thanks for the help guys.

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