Author Topic: Electrical mystery problem (V50 III)  (Read 392 times)

Offline gallazblue

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Electrical mystery problem (V50 III)
« on: October 18, 2021, 09:47:20 AM »
Hey everyone,

I'm having a bit of trouble troubleshooting this one electrical issue :

Context :
- I have aftermarket turn signals
- An upgraded regulator/rectifier (Electrosport ESR450)
- Rotor and brushes are new
- Regulator works perfectly and charges the battery properly (finally)
- Yuasa 53030 battery is new but was left almost empty during a whole month due to alternator issues, but still works and maintain volt nicely
- Left side blinkers work as they should

Problem :
- Front right blinker doesn't work at all
- Back right blinker only works when alternator is sending juice (from around 3000 rpm)
- Dashboard Headlight Led is almost off when under 3000 rpm

Where could the problem come from ? Grounds ? Battery issue ?

Thanks,

Enzo




Offline nc43bsa

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Re: Electrical mystery problem (V50 III)
« Reply #1 on: October 18, 2021, 10:00:06 AM »
I would check all grounds and power connections in the affected circuits, but first, have you checked the battery voltage below and above 3000 RPM?
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Re: Electrical mystery problem (V50 III)
« Reply #2 on: October 18, 2021, 10:13:33 AM »
What do you mean by this? "Dashboard Headlight Led is almost off when under 3000 rpm".
Charlie

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Re: Electrical mystery problem (V50 III)
« Reply #3 on: October 18, 2021, 12:54:57 PM »






i had no end of electrical gremlins on my V50III.  It turned out they had grounded the system to a painted frame  After I sanded and cleaned the area, reattaching the ground, things started working.  It is worth a shot.


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Re: Electrical mystery problem (V50 III)
« Reply #3 on: October 18, 2021, 12:54:57 PM »

Online Wayne Orwig

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Re: Electrical mystery problem (V50 III)
« Reply #4 on: October 18, 2021, 01:09:27 PM »
Problem :
- Front right blinker doesn't work at all
- Back right blinker only works when alternator is sending juice (from around 3000 rpm)
- Dashboard Headlight Led is almost off when under 3000 rpm

As asked, what in the world is a "Dashboard Headlight Led"?

From your description, it almost sounds like a loose connection or relay contact, and engine vibration is sort of making it connect.
Scientist have discovered that people will believe anything, if you first say "Scientists have discovered...."

Offline gallazblue

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Re: Electrical mystery problem (V50 III)
« Reply #5 on: October 18, 2021, 01:56:10 PM »
I would check all grounds and power connections in the affected circuits, but first, have you checked the battery voltage below and above 3000 RPM?

Ok! I've already checked them and they seem fine, battery at idle is around 12.8v et revving around 14.4v
Battery seems fine ?

Offline gallazblue

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Re: Electrical mystery problem (V50 III)
« Reply #6 on: October 18, 2021, 02:08:11 PM »
As asked, what in the world is a "Dashboard Headlight Led"?

From your description, it almost sounds like a loose connection or relay contact, and engine vibration is sort of making it connect.

The headlight light indicator* that was replaced by a led bulb (I mentioned the type in case the problem could come from there).





Actually I've replaced the original defective relays by new ones recently, I'll be checking them tomorrow.


Offline berniebee

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Re: Electrical mystery problem (V50 III)
« Reply #7 on: October 18, 2021, 02:09:16 PM »
If your left signals are working properly, the flasher unit, the battery and charging system are fine.

If you can swap blinker bulbs, put the both the left ones into the right side blinkers and see what happens. If they are one piece blinkers (Non removable bulbs) swap them to make sure it's not a defective blinker unit. A quicker way to test the right side blinkers is to hook them up directly to the battery, but do this only if you are confident you won't short the battery to ground.  Do you have some jumper leads with clips? Alternatively you could (Very carefully) connect the blinker directly to the battery once the blinker is detached.
If you're not sure how, post a pic of the blinker and its' wiring.

If it's not defective bulbs/blinkers:

A test light is handy here. (Or a mulitmeter.) Ground the test light's clip (or meter negative wire)  to the frame and test the light (meter) by touching the probe to the battery + , or a known live 12 volt terminal at the fuse box. Now see if you get a blinking test light at say, one of the front right blinker wires when the blinker switch is on . If there is only one wire going to the blinker, then that should have the blinking 12V.  No blinking light means trouble with wiring between the blinker switch and the blinker, or possibly a problem with the blinker switch itself.

If you get the blinking 12V:

Look at the wiring.  If there is only one wire going to each blinker, then the return path for current is through the metal part of the blinker and it's electrical connection to the frame. The metal of the blinker unit has to touch an unpainted , non rusty spot on the frame to make a good connection. If there are two wires,  then check for blinking voltage on one - the other is ground. That ground wire wire should be attached to a clean unpainted spot on the frame.

Hope that helps.  Pics of the blinker wires and the connections might be helpful.




Offline gallazblue

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Re: Electrical mystery problem (V50 III)
« Reply #8 on: October 18, 2021, 02:11:05 PM »

i had no end of electrical gremlins on my V50III.  It turned out they had grounded the system to a painted frame  After I sanded and cleaned the area, reattaching the ground, things started working.  It is worth a shot.

Wow, that's valuable info. Which one was it ? Because, if I remember correctly, under the headlight there is a ground connected to the frame that might be painted. I'll be checking it out tomorrow.

I appreciate the help.

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Re: Electrical mystery problem (V50 III)
« Reply #9 on: October 18, 2021, 02:20:14 PM »
A Honda CB100 I had did that; the attachment was ok but then the earth went through the steering head bearing, giving somewhat intermittent earth.  Fixed when a dedicated earth was run directly back to the battery.
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Offline gallazblue

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Re: Electrical mystery problem (V50 III)
« Reply #10 on: October 18, 2021, 02:26:58 PM »
If your left signals are working properly, the flasher unit, the battery and charging system are fine.

If you can swap blinker bulbs, put the both the left ones into the right side blinkers and see what happens. If they are one piece blinkers (Non removable bulbs) swap them to make sure it's not a defective blinker unit. A quicker way to test the right side blinkers is to hook them up directly to the battery, but do this only if you are confident you won't short the battery to ground.  Do you have some jumper leads with clips? Alternatively you could (Very carefully) connect the blinker directly to the battery once the blinker is detached.
If you're not sure how, post a pic of the blinker and its' wiring.

If it's not defective bulbs/blinkers:

A test light is handy here. (Or a mulitmeter.) Ground the test light's clip (or meter negative wire)  to the frame and test the light (meter) by touching the probe to the battery + , or a known live 12 volt terminal at the fuse box. Now see if you get a blinking test light at say, one of the front right blinker wires when the blinker switch is on . If there is only one wire going to the blinker, then that should have the blinking 12V.  No blinking light means trouble with wiring between the blinker switch and the blinker, or possibly a problem with the blinker switch itself.

If you get the blinking 12V:

Look at the wiring.  If there is only one wire going to each blinker, then the return path for current is through the metal part of the blinker and it's electrical connection to the frame. The metal of the blinker unit has to touch an unpainted , non rusty spot on the frame to make a good connection. If there are two wires,  then check for blinking voltage on one - the other is ground. That ground wire wire should be attached to a clean unpainted spot on the frame.

Hope that helps.  Pics of the blinker wires and the connections might be helpful.

First, thanks for the detailed answer. It's going to make the troubleshooting way easier.

I've already tried to switch the lights but blinker worked fine. I'll be testing the blinker wire tomorrow.
So either blinker 12v wiring, blinker switch or ground.


I'll be posting tomorrow after some testing.

I really appreciate all the help.





Offline berniebee

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Re: Electrical mystery problem (V50 III)
« Reply #11 on: October 18, 2021, 02:31:46 PM »
The headlight light indicator* that was replaced by a led bulb (I mentioned the type in case the problem could come from there).





Actually I've replaced the original defective relays by new ones recently, I'll be checking them tomorrow.
Guzzi refers to that as the parking light indicator, because in certain countries the headlight shell contains a "parking bulb" as well as the hi and lo beam headlight. I believe that parking light bulb is in parallel with the speedo and tach illumination- are they normal brightness? If so, the problem is probably with the parking bulb/socket or wiring within the console.

Offline Kiwi_Roy

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Re: Electrical mystery problem (V50 III)
« Reply #12 on: October 19, 2021, 03:33:39 AM »
You dont say what year so i'm going to pick 1977
https://www.thisoldtractor.com/guzzi007/schematics/1977_V50.gif
First of all the front and rear lamps on either side are wired together so whatever one does the other should do also. There are however a few more joints between the front and rear.
The alternator should have nothing to do with it.
I would start checking grounds, take about 10 ft of wire and connect somewhere on the engine then use the other end to supplement any lamp ground.
If you have aftermarket LED turn indicators they can often be overwhelmed by the dash lamp, you need to add a pair of diodes leading to the dash lamp to prevent crosstalk.
Left side---->|----------|---------|<-------Right side
                                  |
                                  |
                                  |--------------(lamp)--------->Chassis (ground)
This arrangement also works if you have an LED dash lamp
« Last Edit: October 19, 2021, 03:54:52 AM by Kiwi_Roy »
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Re: Electrical mystery problem (V50 III)
« Reply #13 on: October 19, 2021, 08:39:07 AM »
I have LED bulbs in both the signals and in the indicator lights on the "dash" in my V50 III. Since there are two dash lights (not one for both), there should be no possibility of "cross talk" and no need for any diode(s).
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Offline berniebee

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Re: Electrical mystery problem (V50 III)
« Reply #14 on: October 19, 2021, 09:48:08 AM »
If your left signals are working properly, the flasher unit, the battery and charging system are fine.

If you can swap blinker bulbs, put the both the left ones into the right side blinkers and see what happens. If they are one piece blinkers (Non removable bulbs) swap them to make sure it's not a defective blinker unit. A quicker way to test the right side blinkers is to hook them up directly to the battery, but do this only if you are confident you won't short the battery to ground.  Do you have some jumper leads with clips? Alternatively you could (Very carefully) connect the blinker directly to the battery once the blinker is detached.
If you're not sure how, post a pic of the blinker and its' wiring.

If it's not defective bulbs/blinkers:

A test light is handy here. (Or a mulitmeter.) Ground the test light's clip (or meter negative wire)  to the frame and test the light (meter) by touching the probe to the battery + , or a known live 12 volt terminal at the fuse box. Now see if you get a blinking test light at say, one of the front right blinker wires when the blinker switch is on . If there is only one wire going to the blinker, then that should have the blinking 12V.  No blinking light means trouble with wiring between the blinker switch and the blinker, or possibly a problem with the blinker switch itself.

If you get the blinking 12V:

Look at the wiring.  If there is only one wire going to each blinker, then the return path for current is through the metal part of the blinker and it's electrical connection to the frame. The metal of the blinker unit has to touch an unpainted , non rusty spot on the frame to make a good connection. If there are two wires,  then check for blinking voltage on one - the other is ground. That ground wire wire should be attached to a clean unpainted spot on the frame.

Hope that helps.  Pics of the blinker wires and the connections might be helpful.

Just thought of something. Without bulbs in the circuit (Or a bad bulb) you may not measure a "blinking" 12 volts, but a steady 12 v instead. That's normal.

Offline berniebee

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Re: Electrical mystery problem (V50 III)
« Reply #15 on: October 19, 2021, 09:50:58 AM »
I have LED bulbs in both the signals and in the indicator lights on the "dash" in my V50 III. Since there are two dash lights (not one for both), there should be no possibility of "cross talk" and no need for any diode(s).

 :thumb:

Offline Kiwi_Roy

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Re: Electrical mystery problem (V50 III)
« Reply #16 on: October 19, 2021, 03:53:47 PM »
As you say if you have two dash lamps there should be no cross-talk but flashers can do some weird things sometimes.
One really obscure complaint I heard was the indicator lamps of a Griso. When the owner turned off the bike the rear indicators (LED) would be on at partial brightness, it turns out that the CARC bikes pass a tiny current through each lamp to check their integrity, this current is only 40 microamps, not enough to drain the battery but always present, it was enough to light up the particular LED bulbs he had chosen, the solution was to put a 1 K resistor in parallel with each lamp.
LEDs depending on the configuration can draw such a tiny current to light. There was nothing at all wrong with his wiring, I was able to replicate the condition on my Griso.
Some direction indicators have several lamps in parallel, others have them in series.
« Last Edit: October 19, 2021, 03:58:42 PM by Kiwi_Roy »
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Re: Electrical mystery problem (V50 III)
« Reply #17 on: October 19, 2021, 03:58:46 PM »
I would load test the battery or swap a known good battery in and test everything.  If it was left discharged for a month the plates are probably sulfated.  Also check battery and frame grounds. Good luck and let us know?
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Offline Alfetta

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Re: Electrical mystery problem (V50 III)
« Reply #18 on: October 19, 2021, 04:08:50 PM »
I don't know about your V50III  but I do know that LED's draw tiny amounts of current and some "blinker units" will not function correctly if the current isn't up to designed specs.  I was considering changing the lamps in my 71 Fiat, but this problem gets even worse with the bi-metallic flashers of old, they need lots of current...

hope you muster through... 
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Re: Electrical mystery problem (V50 III)
« Reply #19 on: October 19, 2021, 04:33:18 PM »
I don't know about your V50III  but I do know that LED's draw tiny amounts of current and some "blinker units" will not function correctly if the current isn't up to designed specs.  I was considering changing the lamps in my 71 Fiat, but this problem gets even worse with the bi-metallic flashers of old, they need lots of current...

hope you muster through...

An electronic flasher (about $7-$10) is cheap and fixes the "fast flash" issue. My V50 III and Convert are all LED with zero issues. I stopped using bi-metallic flashers due to poor quality, long before going with LEDs, most didn't work correctly right out of the box.
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Offline berniebee

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Re: Electrical mystery problem (V50 III)
« Reply #20 on: October 19, 2021, 04:54:39 PM »
An electronic flasher (about $7-$10) is cheap and fixes the "fast flash" issue. My V50 III and Convert are all LED with zero issues. I stopped using bi-metallic flashers due to poor quality, long before going with LEDs, most didn't work correctly right out of the box.

Agreed. These days the bi-metallic ones are, as my Scottish friend says, shyte.  Load independant (electronic) flasher units will flash at the same rate whether you have one LED or four incandescent signal lamps connected to them. When I rewired my SP, using an electronic flasher eliminated the need for a separate 4 way (Hazard ) flasher unit. Whether I've got just the turn signals on or all four bulbs going, the flash rate is the same.  Available on Aliexpress for under $5.


Offline Kiwi_Roy

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Re: Electrical mystery problem (V50 III)
« Reply #21 on: October 20, 2021, 05:11:48 AM »
The Fast Flash is to let you know you have a lamp out, they also do a real long flash if you get a short, it won't work with LEDs though.
The CARC bikes will throw up a picture of a lamp if one goes out but they sometimes need a small drain resistor e.g. 1,000 Ohms across each lamp, most modern bikes don't have a relay, flashing is a dash function.
-------------------------------------------------
I'm one of those old geezers who drives along for miles with my indicator flashing, I got a wake up call not long ago when a driver assumed I was going around the corner and shot out from the intersection. On my Eldorado I added a lever from the clutch to self cancel the indicator switch, thats a bit annoying too but I can hold it on, my friend had an FXR Harley with a button on each bar, I thought that was a good solution.
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« Last Edit: October 20, 2021, 05:28:23 AM by Kiwi_Roy »
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Re: Electrical mystery problem (V50 III)
« Reply #22 on: October 20, 2021, 11:46:04 AM »
I found the source of some weird issues to be wires melted together inside the rear turn signals - may not be your culprit, but to check it is not too much work.
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Offline berniebee

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Re: Electrical mystery problem (V50 III)
« Reply #23 on: October 21, 2021, 10:52:38 AM »
...most modern bikes don't have a relay, flashing is a dash function.
-------------------------------------------------


Yeah, I was surprised to learn recently that modern cars don't have flasher units either. The timing for the flasher is produced by the car's processor. Very stable. You can actually synchronize the flashers of say, two GM vehicles and they will stay in sync for a long time. And the flasher sound? Also produced by the computer and played through the car speakers. 

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