OP
UTC

Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
 
Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
UTC quote
How is it that the horn works by breaking the circuit?
I am getting the horn working only when the pilot light is off, and the headlight does not come on at all.
What are the connections that should be made with each of the three poisons of the light switch?
@mjrally avatar
UTC

Veni, Vidi, Posti
73 & 74 Rally, 76 ET3, 80 P200, 61 Ser 2, 65 Silver Special,, 2015 HD Road Glide Special
Joined: UTC
Posts: 5258
Location: Oceanside, CA
 
Veni, Vidi, Posti
@mjrally avatar
73 & 74 Rally, 76 ET3, 80 P200, 61 Ser 2, 65 Silver Special,, 2015 HD Road Glide Special
Joined: UTC
Posts: 5258
Location: Oceanside, CA
UTC quote
Do you have a wiring diagram for your scooter?

http://www.scooterhelp.cowww.scooterhelp.com/electrics/wiring/VMA1_VMA2_V9SS2.pdf

You will need to remove the headlight and open up the switch. Make sure all the wires are in good shape, grounds are clean and tight and then send pics of the front and back of the switch so there's more info on what part of the switch does what.
@oopsclunkthud avatar
UTC

Banned
3:5
Joined: UTC
Posts: 9053
Location: San Francisco
 
Banned
@oopsclunkthud avatar
3:5
Joined: UTC
Posts: 9053
Location: San Francisco
UTC quote
IIRC The power splits and goes to one side of both the horn and the switch, the other side of the horn goes to the other side of the switch (the horn and switch are in parallel. When the button is not pressed the switch shorts across the horn, and when pressed the power must pass through the horn.

On the outbound side of the horn and button the power can take two paths to ground depending on the lighting switch position.
1. Pilot off: send the horn straight to ground.
2. Pilot on: send it to the pilot bulb and from there to ground.

In case 2 the pilot bulb must not be burnt out and must be of the correct volt/wattage since the current has to pass through both the horn and the light (in series).

Does the pilot bulb work when the horn is not pressed? does it work when it is pressed?
OP
UTC

Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
 
Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
UTC quote
VMA1T electrics
MJRally - see attached wiring diagram. This seems to correspond well, but I have had to make a couple of adjustments to accomodate shortcomings in the rewiring done by a third-party. The photo shows the back of the handlebar switch BEFORE I added an additional 'cut out' red wire from the terminal M to the ignition switch (not shown on the original wiring diagram) (and I've marked these up).

oopsclunkthud - I'll have a study of your advice in the morning.

Many thanks to both.
Forum member supplied image with no explanatory text
pdf
522kb
@mjrally avatar
UTC

Veni, Vidi, Posti
73 & 74 Rally, 76 ET3, 80 P200, 61 Ser 2, 65 Silver Special,, 2015 HD Road Glide Special
Joined: UTC
Posts: 5258
Location: Oceanside, CA
 
Veni, Vidi, Posti
@mjrally avatar
73 & 74 Rally, 76 ET3, 80 P200, 61 Ser 2, 65 Silver Special,, 2015 HD Road Glide Special
Joined: UTC
Posts: 5258
Location: Oceanside, CA
UTC quote
Oops knows these old AC systems better than I do. Try what he said first.

Is the area circled exposed copper wire? That could be grounding out when the switch is screwed in to the headset. If you're handy with a multimeter see if you can check the switch. Make sure you're getting continuity. I'm guessing the switch is off, pilot bulb only, everything on?
Forum member supplied image with no explanatory text
OP
UTC

Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
 
Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
UTC quote
VMA1T electrics
Between you you may well have 'hit the sweet spot'. I am aware that someone has put a 12v bulb into the pilot light, and I have been trying to source a 6v 5w replacement at the same time as trying to complete the rebuild, together with a 6v speedo festoon which is missing altogether. It didn't cross my mind that the pilot might be drawing all the power. I'll check out that wiring this morning but, in the meantime, I suspect you guys could tell me where to find 6v bulbs. I have tried my local Halfords and M/c shops, and looked on the web, but without success to date.
@mjrally avatar
UTC

Veni, Vidi, Posti
73 & 74 Rally, 76 ET3, 80 P200, 61 Ser 2, 65 Silver Special,, 2015 HD Road Glide Special
Joined: UTC
Posts: 5258
Location: Oceanside, CA
 
Veni, Vidi, Posti
@mjrally avatar
73 & 74 Rally, 76 ET3, 80 P200, 61 Ser 2, 65 Silver Special,, 2015 HD Road Glide Special
Joined: UTC
Posts: 5258
Location: Oceanside, CA
UTC quote
Try Beedspeed in Grimsby
OP
UTC

Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
 
Lurker
Vespa125 VMA1T
Joined: UTC
Posts: 4
Location: Ashtead, UK
UTC quote
VMA1T electrics
Many thanks MJ. I have placed an order with Beedspeed. Should be here in a couple of days.
DoubleGood Design banner

Modern Vespa is the premier site for modern Vespa and Piaggio scooters. Vespa GTS300, GTS250, GTV, GT200, LX150, LXS, ET4, ET2, MP3, Fuoco, Elettrica and more.

Buy Me A Coffee
 

Shop on Amazon with Modern Vespa

Modern Vespa is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com


All Content Copyright 2005-2025 by Modern Vespa.
All Rights Reserved.


[ Time: 0.0151s ][ Queries: 4 (0.0066s) ][ live ][ 327 ][ ThingOne ]