Modern Vespa

I hate electrical problems!

That's mostly because I don't understand them. Sure, I know the basics of how a 12 volt DC system works but what I don't understand is how it DOESN'T work! That what I'm dealing with now. The electrical system on Spermy (https://modernvespa.com/forum/topic168825?highlight=spermy) died and I have no idea why or what to do about it.

In November I shut down Spermy for the winter, disconnected the positive and negative battery cables and attached my battery tender. Then in early February I reconnected the cables, more or less, and went for a ride. I found out later that I had connected the negative battery cable and the positive cable for the Nautilus horn but I forgot to connect the main positive battery cable. As I left the house, I saw that all the DC lights (except the neutral light) got really bright and then went out. I reconnected the positive battery cable but all the lights (except the neutral light) still don't work. I checked the fuse of course but it is still intact and the bulbs are still good so I have no idea where to begin looking for the problem. I haven't sat down and tested the continuity of the wiring, mostly because I don't know where to begin.

Might this be a problem with the voltage regulator? (If that's a dumb question, please refer to sentence #2 above)

I'd appreciate any suggestions.

Which lights are DC lights on your scooter? I'm not familiar with it and looking at the wiring diagram it doesn't say. My Stella for instance has 12 volt AC and DC bulbs.

What an idiot!!!!








Nah just kidding. It happens to all of us one time or another. If the fuse and battery really are good, I'd move up to the keyswitch. Test for DC voltage in (red wire usually) and then dc out with the key turned (green white/white combo I think). If you have a bus bar off the battery might as well test for voltage there before moving into the keyswitch.

As far as a problematic voltage regulator, I've noticed they overcharge your battery, or just die completely. Nothing in between. Never intermittent for DC but sometimes for the AC circuit. (Had an old P with a flickering headlight that actually got traced to a bad VR).

Headlight is AC but I think that everything else is DC.

I should have added that Spermy is a 1980 P200 and, other than the Nautilus horn and LED turn signal bulbs and LED stop/tail light bulbs, it is all stock

Yes MJRally... I'm an idiot But anyone who follows me on the forum know that already.

Fortunately, I know that there are a lot of non-idiots here as well.

I'm out of town for the weekend but I'll check out the keyswitch when I get back

Am I looking at this correctly in that with no battery everything should still function when running?

There isn't a voltage regulator for charging the battery?

If everything was working I'd be worried that the positive lead that wasn't connected touched ground, creating a direct short and burned up the lighting and charge coil for the battery at the stator. The fuse should have opened instantly with a direct short but maybe it wasn't fast enough?


http://www.scooterhelp.com/electrics/wiring/VSX1T.USA.after.pdf


I would verify with a meter you have around 12.5 volts dc at the battery not running just turned on. If the battery is bad you may have no load voltage but as soon as you turn the system on and load it down it will drop to something to low for lighting to function. I always say to measure is to know.

That diagram doesn't label the regulator/rectifier but the two are combined.

Without a battery installed you'll barely get any dc voltage out to the bulbs from the rectifier. Occasionally you'll see a glow from the taillight but it's not enough for regular use.

Like you said, get the meter out and confirm

I beginning to see some progress!

I finally got a chance this weekend to delve into this Electrical Hell and started by following the recommendations from MJRally and Christopher. I found out that the battery is good and that I have power into and out of the ignition switch so then I started examining each of the bulbs etc.

The neutral light on the headset works fine so I left that alone

The brake light works with the foot petal but the taillight does not so I removed the LED bulb and replaced it with an incandescent bulb and now both parts work. That's a two-element bulb and the taillight portion of the LED bulb was burned out so I'll order a new one.

None of the turn signal lights worked even though all four of the LED bulbs tested good. I replaced them with incandescent bulbs and I replaced the flasher with an old analog flasher and now all 4 work properly even though the indicator light on the headset does not.

I suspect that I burned out the LED flasher but I don't know how to test the old one. I'm guessing that I connect the two battery leads to the two outside contacts (does positive/negative matter?) and an LED bulb to the center contact and then to a ground, I'll see if the unit flashes or not. Is that correct? If it doesn't work, I'll replace it and go back to the LED turn signal bulbs.

My add-on nautilus horn didn't work so I replaced the relay with a new one and now it works.

The headlight was burned out and I'll replace that with a new one.

All I have left now is the bulbs in the headset and I'll look into those later on.

WOW - Progress is right! Good job troubleshooting! And we all know how much you love working on electrical stuff.

Yeah... right!

I'm working on the dead bulbs in the headset and from what I can see the Neutral Light and the Speedometer light use the same bulb which looks like 12 volts, 3 watts. The bulb I have in the Neutral Light doesn't work in the Speedometer socket so it looks like something is loose there but I'll trace it down later

I found that bulb at Scooter Mercado but I can't find the bulb for the Hi/Lo Beam indicator and the Turn signal. It looks like they are the same bulb but I can't read any markings on the old one so I don't know what it is. Can someone identify that for me and tell me who carries it?

Also, are there LED versions of these bulbs?

This may sound crazy, but taking the bulbs down to the local AutoZone, Napa, or O'Reilly's may net you some LEDs with the same type of base, or possibly the correct bulbs in incandescent.

I found the bulbs for the 62 Allstate at AutoZone.....

NOW WHAT HAVE I DONE??

For the last week I've known I was going to have to replace part of the Dreaded Green Wire. I replaced the section from the horncast junction box to the CDI a couple of months ago but I recently found that the section from the junction box to the ignition switch and the kill button was crumbly badly and would have to be replaced soon.

For the past few days I have been starting the engine just to make sure it was still running (it was) but for the last few days I couldn't turn off the engine with the key but had to use the kill button instead. I could still use the key to turn on the Neutral light and the tail light.


This morning I was going to go for a ride but Spermy wouldn't start. I pulled the DGW from the CDI and it started right up so I knew the DGW was shorting out someplace else. I clipped the crumbling section of the wire at the ignition switch (below) and at the horncast junction box and replaced it and now the ignition and kill button work as they should... but the other lights don't.

It acts like the neutral light and the tail light have gone from DC to AC. That is, when I turn on the ignition switch, neither bulb comes on but they both turn on and fluctuate when I run the engine... like the headlight. Something like this was happening when I started having electrical problems a couple of months ago.

What have I done and how do I fix it?

Never mind... blown fuse

I am Bad! I decided I needed a USB port/hub and installed 1 on my LXV150ie and have compromised my electrical system and have not yet sorted out what stupid thing I managed to do... so yes, the world of sympathy for anyone with a scoot and electrical issues!

I'm confused about fuses. See three entries above...NOW WHAT HAVE I DONE??. Apparently when the main fuse blew, it caused the neutral light and the tail light to act like they were AC powered and fluctuated as the engine speed fluctuated. Is that normal? In two previous PXs when the fuse blew, all the DC bulbs and the horn just stopped. Why would they fluctuate with the engine on this PX? Any thoughts?

If I had two identical fuses in line, which one would blow first... the one closer to the battery or the one further away?

I don't really like the stock 8 amp VW fuse and I want to change it to a blade fuse. I'm wondering if it would be better to use the larger, regular fuse or the smaller mini fuse? ... I've used the smaller fuse in the past. 10 amp or 7.5 amp?

Maggiegirl, how did you hook up the USB port? I've seen guys do something similar by using a busbar/terminal strip between the battery and the port. That might help you eliminate, or at least isolate the problem

No, but that looks like it could fix my problems, LXV is on my list but first is the old house and code violations with the electrical wiring service entrance and gee, when they replaced the old meter with smart meters over 2 years ago it would have been nice to have been notified, now, 1/2 through the tankless water heater job I learn I have code violations and the power lines coming to the house cannot carry enough electricity to upgrade for the tankless water heater. Such are the joys of old house ownership but then my Cheap old house means I have had scooter funds$. Thanks, I will have to try that...

Yeah, some of these "new-fangled gizmos" like Smart Meters, are more trouble than they're worth. I guess that's why I prefer Shifties to Twisties

Does anyone have an opinion on using a Regular fuse as opposed to a mini fuse? Is 10 amps ok?

If you look at the fuse link element, they are the same.

I wouldn't go larger than the factory fuse size. That fuse is meant to protect the scooter wiring and other components in case of a short to ground or other high current draw event.


Whether you switch to an ATC full size or ATM miniature, I would use a 7.5 amp fuse. Didn't find an 8 when I was looking.

You could switch to a glass AGC style holder and get an 8 amp size.

The 2005 px150 uses 7.5 amp ATC fuse.

Ok, I'll go with the 7.5 amp fuse but I'm still curious about using the full size or the mini fuse.

I know that they are both the same electronically but does anyone have a preference for one over the other and WHY?

When you have 18 fuses a mini fuse box is more compact. I'm not sure there is a difference for us on our scooters. Last time I bought the larger ATC style because its what is in my cars and was easy to find on the shelf at my local advanced auto.

https://itstillruns.com/difference-between-atc-atm-fuses-7526605.html

Since I have a habit of short circuiting things whenever I work on anything electrical, I like to pull the fuse before I do anything else but Spermy still uses the stock ceramic fuse and I find the twist-apart fuse holder really annoying. The wires always get twisted, so today I added a simple toggle switch between the battery and the fuse holder. Much easier.