Vespa P range indicator issues. A beginners guide.

[sbwnik]

Nearly all P range Vespas and variants (Cosa, PK, most LML) use a simple AC system for the indicators.

Simple version

The current generated by the flywheel/stator goes to the regulator, and then on to the indicator relay. From there it is sent down two wires, one carrying current to power the rear indicators, the other the front. When the two wires reach the handlebar switch each is split, giving four wires in total, and these run to the indicators.

That's simple enough to visualise - One to two to four, with the two taking it in turns to carry the current as it gets switched by the relay. This explains why Vespa indicators flash alternately rather than together, ensuring that there is a constant 21w load on the system, rather than 0W-42W-0W-42W..

Slightly more descriptive version

The power for the indicators comes from the regulator, a silver, ribbed, hexagonal device located under the left hand panel and behind the spare wheel (and battery if fitted). If you examine this, you'll find a wire running to the small square (often green) block sitting in the same area. This is the indicator relay.

The relay has three connectors, and the wire from the regulator runs to the most central pin. A simple description of how the relay works is to imagine a pendulum inside, swinging from side to side and contacting the two remaining pins in turn.
These other two pins have wires which run up the frame to the indicator switch. From here, the current is directed by the switch to the four wires which run to the indicator bulbs.

Fault finding

Because of the simplicity of the system, fault finding is pretty simple.

If all the indicators are out, then the chances are that the wire between regulator and relay has become broken or dislodged. Check and plug back in/replace as needed.

If both indicators at one end have failed, then check the wires between the relay and the switch. You may need to do a continuity test to do this properly (See end). 90% of problems like this are on this part of the circuit.

If both indicators on one side have failed. This is very rare, and I've only ever known it being down to a damaged switch, generally with the wiring being pulled tight and pulling away.

If only one is out, then the problem will be somewhere between switch and earth.

Simple as that!


All that said, there are a few predictable and regular problems.

Firstly, if you get any problems, always check the bulbs. I know it sounds obvious, but the frequency in which you see people chasing all sorts of issues for a blown bulb...
Next are the panels - the connectors at the front can get filled with gunk, making for a poor connection, and the earthing connection through the spring on the top can get similarly affected. Keep them clean and a lot of problems can be avoided.
Finally, front indicator wires are very vulnerable. Any problems at the front, check the two wires that attach to each bulb, these are easily dislodged.


Continuity testing
The easiest way to check for broken wiring is a continuity test: Grab a cheap electrical meter and set to resistance (ohms - the little picture that looks like a bridge!) and touch one probe to each end of the wire you need to test. Hopefully the reading will be zero ohm, or near enough. Anything higher than a small amount suggests that there is an issue with a broken wire.



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There are some 4 pin relays versions, I'll come back to them another day when I've got my head around how they work...




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Thanks to KRU251 for his input
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[sbwnik]

I'm also going to add resolved other problems too as they come up. Or feel free to add them yourself once you've got a definitive solution, and here's the first one, courtesy of Chords.

The fault given was that the front indicators flashed once, and then the rear ones stayed on.

After some diagnostic guesswork, it was found that the relay was at fault (presumably jamming on one pole) and the problem was solved by replacing the unit.

>>>>>>>>>Original thread here<<<<<<<<<<

[chevrons1]

Apr 10, 2014 9:49:12 GMT sbwnik said:

Nearly all P range Vespas and variants (Cosa, PK, most LML) use a simple AC system for the indicators.

Fault finding

Because of the simplicity of the system, fault finding is pretty simple.

If all the indicators are out, then the chances are that the wire between regulator and relay has become broken or dislodged. Check and plug back in/replace as needed.

If both indicators at one end have failed, then check the wires between the relay and the switch. You may need to do a continuity test to do this properly (See end). 90% of problems like this are on this part of the circuit.

If both indicators on one side have failed. This is very rare, and I've only ever known it being down to a damaged switch, generally with the wiring being pulled tight and pulling away.

If only one is out, then the problem will be somewhere between switch and earth. Having just had an indicator problem myself please check the wiring within the switch.  If I had done this I would not have had to remove tank and headset cover!

Simple as that!



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Thanks to KRU251 for his input
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[leishy62]

Hey boys n girls, looks like my PX150 has a bit of an oil leak from the rear hub, now I haven't pulled one apart for a wee while, can someone refresh my memory, do I need to split the casing or can I fit the seal from the outside? I have looked online but am getting lots of conflicting info...
Cheers guys!

[jimslinger]

Hi,

I have a 1999 Px125 Disk. My indicators seem to be playing up. They work for a short while and then the lights stay on contiunously (Both front and rear)  and less brightly. Any ideas?

Thanks

Jim

[henri]

duff relays my best guess . H

[rambandit]

I got abit of a headscratcher to add to this,  n/s indicators work fine but o/s ones flash erratically along with the pilot bulb !!
Has anyone had this issue ?  checked connections and cleaned all earths but a bit stumped at present

[scooterg]

Happy I looked this up
Rear left indicator stopped working,Was just about to remove tank as there was no live feed..
Then seen this post,,,So opened the switch up AND there it was one little wire sitting,all alone laughing at me
Put back in place,,,,And all s well again 👍
Wires in there are getting a bit tight,,Might have to do something very soon

[bulla80]

Excellent post will follow advice on here, all indicators not working on my PX200, had a new stator plate fitted and they came on for a bit, once I got panels back on and went for a ride they had stopped again, jiggled the wires going into the junction box on top of the flywheel? (not sure if that is the correct term, bear with me I work in IT!!) and they came on for a bit but went off again when I put the panels back on, so I gave up, had another look a few days later and now the green light on the speedo stays on but nothing from the indicators and now when I do a hard right my horn sounds!! I could have this a a feature I guess but I really would like my indicators back!!! Any advice greatly appreciated.
Thanks in advance.
Adam

[mijapxman]

Bulla80,if your indicators were working before you changed the stator plate,their is a good chance you have either pulled a wire of at the stator or trapped a wire/wires as you tightened the three screws that hold the stator on.

Mij☺

[bulla80]

May 10, 2018 19:38:19 GMT mijapxman said:

Bulla80,if your indicators were working before you changed the stator plate,their is a good chance you have either pulled a wire of at the stator or trapped a wire/wires as you tightened the three screws that hold the stator on.

Mij☺

Thanks for the reply, I had a professional change the stator, not sure I could get it off myself, I will check all the options this weekend, I did notice that the box on top of the flywheel was a bit of a squeeze for him to get the cables in, something in there maybe, lets see how I get on, thanks again. 

[jonboy]

Having problems on a p200 electric start 03 model
my front indicators would go solid and no rear indicators when in use I put this down as bad earth so I cleaned all earthing points.
still had nothing so put new indicators in with a direct earth to frame as the original ones were a bit tatty and had the same problem.
I did a continuity test and also checked the voltage supply reaching the indicator unit all was good.
So I bought a new flasher unit then I only had solid rear indicators I am very confused

Would 2 duff flasher relays cause this? Does not having the battery on effect things?
Any other ideas?

Any help or ideas be great thanks in advance
Jon

[willp]

Hi all, I am pretty new to scootering having recently bought an 05 plate PX125 from a dealer in Birmingham. I have an issue with the rear offsite indicator which went from working intermittently to not working at all.

All other indicators work fine so it suggests the problem is between the relay switch and the rear light. I have checked all the usual culprits and ruled out those.

Having done a series of fault finding using a multimeter, I am almost certain the issue is associated with a poor / corroded connection behind the spring loaded plug which the rear side panel pin is inserted into.

I am trying to find out if it is possible to prize out / remove the spring loaded chassis plug to check the connection behind it? (See photo below)

The original dealer isn’t interested in helping me unfortunately.

Anything suggestions or advice would be gratefully received.
Thanks
Will

[ironsloth]

That floor looks better than mine, but mines had 12 years of constant abuse.... Reckon it is corroded as I can see the paint bubbling up near it. Might be able to polish it up inside with a cleaning head on a drill? Ever so carefully mind.

[mijapxman]

Jun 14, 2018 7:49:07 GMT willp said:

Hi all, I am pretty new to scootering having recently bought an 05 plate PX125 from a dealer in Birmingham. I have an issue with the rear offsite indicator which went from working intermittently to not working at all.

All other indicators work fine so it suggests the problem is between the relay switch and the rear light. I have checked all the usual culprits and ruled out those.

Having done a series of fault finding using a multimeter, I am almost certain the issue is associated with a poor / corroded connection behind the spring loaded plug which the rear side panel pin is inserted into.

I am trying to find out if it is possible to prize out / remove the spring loaded chassis plug to check the connection behind it? (See photo below)

The original dealer isn’t interested in helping me unfortunately.

Anything suggestions or advice would be gratefully received.
Thanks
Will

Yes it can be removed, the proper way means taking out the petrol tank among other things. Try taping a piece of wet and dry sand paper to a screw driver and use it to clean the connector.

Have you checked you have a good earth wire coming from the indicator to the rear panel,  try removing the earth wire to the panel and cleaning it's contact patch to the panel if you get no connection.

Mij☺

[scooterg]

Before you go that far
Remove the switch at the handlebars , wires become disconnected 
They are famous for this!, mine does it at least twice a year

[willp]

Thanks chaps
Mj - I thought the earth was via the chassis on the PX125 - as far as I’m aware there is no earth wire?

Scooterg - 3 of the 4 indicators work - it’s only the rear offside that doesn’t work.
Could that still be as a result a fault at the switch as you suggest?

[scooterg]

Yes
sounds more and more ike a loose wire at the switch 
it will take you 2secs to open it and have a look
took me 2 fekin days to think of it 😡

[scooterg]

Hey willp
How did you get on with the indicators ?

[grahammilgram]

When my indicators are on and I’m stationary the light is very dim to none existent. As soon as revs rise the lights get brighter is this the norm??

[ironsloth]

Grahammilgram, yes, yes it is.

[smudge]

Apr 11, 2014 23:55:10 GMT sbwnik said:

I'm also going to add resolved other problems too as they come up. Or feel free to add them yourself once you've got a definitive solution, and here's the first one, courtesy of Chords.

The fault given was that the front indicators flashed once, and then the rear ones stayed on.

After some diagnostic guesswork, it was found that the relay was at fault (presumably jamming on one pole) and the problem was solved by replacing the unit.

>>>>>>>>>Original thread here<<<<<<<<<<

Afternoon all. New member here. I’ve just bought a cheap px. It runs ok. I’m having indicator issues. I’d really appreciated some help. 

The indicators come come on and don’t flash. Both sides. Both indicators at the same time. So right side front and rear come on  and stay lit, when the switch is over. Flip the switch the other way, both left side come on and stay lit. I replaced the green flasher relay, brand new one, still the same. No indicator tell tale in the head set, and the horn is knackered and needs replacing. All lights work. Brake lights work. Elect starter relay not fitted. No fuel gauge sender level on head set from the tank. 


Any ideas?

[citydaz]

hi, my suggestion would be first  to check the connections coming from your switch, and then if no joy then buy a new switch.
You know that they all work, you have fitted a new relay so it must be the the wiring / connections from the switch methinks.

[smudge]

Ok, I’ve disconnected the wires from the new flasher relay, leaving just the green/grey wires connected on the green dot spade connector. There is a 12v constant output on each of the 2pinsmwhen the meter is to earth. I’d have expected it to “flash”, on off. I replaced to old relay -exactly the same results. Still waiting on the new handle bar switch, but this constant steady output from the relay is puzzling me somewhat.

[smudge]

New handlebar indicator switch fitted. Same result. Both indicators same side are on when the switch is over. I’m really puzzled about the steady 12v output from the flasher though. Any ideas?

[scooterg]

Where are you,,if you let us know where you are
someone on here might come round and have a look,compare scooter wiring

[smudge]

Essex.


The wiring to the ignition key has been cut, and replaced by a key switch, a on/off button, and a temp gauge for the cylinder head (not connected) 


I’m thinking this is probably the issue, I just understand the relay giving a constant 12v. It’s baffled me, I’d have expected it to switch the 12v from pin to pin so to speak. That’s really got me baffled. Am I expecting the right thing? 

[smudge]

There a chap fairly local who seems to know his stuff, I might pop in to his workshop and have a chat.

[scooterg]

Sounds like the best thing to do
Hopefully it’s an easy fix,,

[sahmiri]

May 10, 2018 9:12:39 GMT bulla80 said:

Un excellent article suivra les conseils donnés ici, tous les indicateurs ne fonctionnant pas sur mon PX200, une nouvelle plaque de stator était installée et ils se sont allumés pendant un moment. Une fois que les panneaux ont été remontés et que je suis reparti, ils se sont encore arrêtés. dans la boîte de jonction sur le volant? (je ne sais pas si c'est le bon terme, je travaille en informatique !!) et ils se sont laissés aller un peu mais sont repartis quand j'ai replacé les panneaux, alors j'ai abandonné, j'ai jeté un nouveau coup d'oeil quelques jours plus tard. plus tard et maintenant le feu vert sur le speedo reste allumé mais rien des indicateurs et maintenant quand je fais une droite dure mon klaxon !! Je pense que je pourrais avoir cette fonctionnalité, mais j'aimerais vraiment que mes indicateurs soient de retour !!! Tout conseil grandement apprécié.
Merci d'avan

Adam iTunes Mobdro TutuApp

Si les deux indicateurs d'un côté ont échoué. C’est très rare et je n’ai jamais compris qu’il s’agissait d’un interrupteur endommagé, le câblage étant généralement tendu et retiré.