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Choppski Samba Member
Joined: November 19, 2011 Posts: 53 Location: UK
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Posted: Tue Mar 06, 2012 4:50 pm Post subject: Generator light on |
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hi guys,
My generator light decided to come on whilst driving and would not go off. Since getting home and turning the engine on the light stays on at low revs, then goes off at high revs.
Checked the voltage on the battery, which was low at 12.3v, but still started the engine. At high revs the voltage stopped at 14.4v so i guess the battery is getting charge. Which would put a faulty regulator or generator out of the question???? or am i wrong?
i've read that if the Gen lights up then the battery isn;t being charged - but my voltmeter tells be different? Could it just be a dirty communicator?
obviously i do not want to drive the beetle in this condition. BTW its a 1302S
what advice/ tips can you provide to help me solve the issue _________________ '71 1302s with stock 1600 & 1982 T25 with 2.0 CU aircooled - living the dream |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15975 Location: North Florida, USA
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Posted: Tue Mar 06, 2012 4:55 pm Post subject: |
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Charge your battery and see if the problem goes away. Your battery at 12.3v is around 25% state of charge. Don't try to troubleshoot any charging system issues until you have a fully charged battery in place. Even if you need to borrow a battery from another car, just for testing.
How old is your battery... they don't last forever. _________________ AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Choppski Samba Member
Joined: November 19, 2011 Posts: 53 Location: UK
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Posted: Tue Mar 06, 2012 5:00 pm Post subject: |
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i'm not sure how old the battery is, but i'll get it charged up and see from there.
i'll let you know! _________________ '71 1302s with stock 1600 & 1982 T25 with 2.0 CU aircooled - living the dream |
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Choppski Samba Member
Joined: November 19, 2011 Posts: 53 Location: UK
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Posted: Thu Mar 08, 2012 4:09 pm Post subject: |
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hello again,
Well i put my fully charged battery back in after changing the dynamo brushes (they were fairly low down, better to knock that issue off the potential list - wow - what a bugger getting that little screw in on the bottom brush pig tail!!!)
started up and no light - get it!!
then after a 10 mile test run to make sure all is well, the gen light came back on. I was driving at night with the lights on...
so i guess that leaves either the regulator or a new dynamo???
thoughts please guys! _________________ '71 1302s with stock 1600 & 1982 T25 with 2.0 CU aircooled - living the dream |
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ROCKOROD71 Samba Member
Joined: January 18, 2012 Posts: 2770 Location: Boston, MA
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Posted: Thu Mar 08, 2012 5:00 pm Post subject: |
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did you check the belt tension? if its loose/ old and slipping, this could cause the light to come on as the generator would not be turning as fast as it should or intermittently turning. this could explain why it comes on when revving low but goes out at high rpms, the slipping belt is turning the generator just enough at high rpm to keep the light off. it shouldn't deflect more than half an inch or so when you push it in from one side. how old is the belt? is it shiny and smooth on the inside. try taking some shims from between the gen pulley and tightening it or replacing it, belts are cheap. _________________ 1971 STD BEETLE- DD-1st car, 1st love. keepin' it stock! 1600DP, Solex 34-3 Mexi Bosch SVDA Dist NOW w/POINTS
1977 WESTY "KrustyKamper" 2L FI
79SuperVert wrote: |
30 years from now, the next guy may not want your girlfriend, but he may want your classic car, depending on how nice you were to it. |
asiab3 wrote: |
Careful guys, a petulant child can grow up to be president these days. |
**winter drivers: no survivors!**rust warrior**#keepbodyshopsbusy** |
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Choppski Samba Member
Joined: November 19, 2011 Posts: 53 Location: UK
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Posted: Thu Mar 08, 2012 5:07 pm Post subject: |
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thanks - i did check the belt tension and it is ok. there are no shiny bits to it and the belt is fairly new.
just to note the light is now staying on when the engine is running - but IS turning off when the engine of off. _________________ '71 1302s with stock 1600 & 1982 T25 with 2.0 CU aircooled - living the dream |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15975 Location: North Florida, USA
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Posted: Fri Mar 09, 2012 5:18 am Post subject: |
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Please tell me you took a voltage reading after you charged your battery?
What was the voltage with the charged battery while the engine was running?
What was the voltage when the light came on? Both with the engine running and off?
Look here for generator tests:
http://www.nls.net/mp/volks/htm/gen.htm _________________ AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Choppski Samba Member
Joined: November 19, 2011 Posts: 53 Location: UK
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Posted: Fri Mar 09, 2012 6:47 am Post subject: |
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the voltage on the battery when charged was 12.9V
when freshly hooked up the battery was at 12.45V initially and then after 5 mins at idle it went up to 12.73V. When i re engine it maxed out at 14.4V.
I didn't check the battery when i got back after the run out....i was soo gutted and it was 11.30pm at night!!!!
i'll check tonight _________________ '71 1302s with stock 1600 & 1982 T25 with 2.0 CU aircooled - living the dream |
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Choppski Samba Member
Joined: November 19, 2011 Posts: 53 Location: UK
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Posted: Fri Mar 09, 2012 1:38 pm Post subject: |
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right, i've just been out and here are my results Ashman:
Battery with the engine off was 12.6V
- the light stayed on after starting
- when running with the engine on the battery showed 12.25V and would not rise above 12.34V even with high revs (as you'd expect with the light on)
- then i went to check the new brushes were sparking and making good contact with the commutator...put my finger on the top brush and the sparks came at higher revs. Amazingly, the light went off!!
Checked the battery at this point and at idle it was only showing 12.35V with the engine still running. I then put the revs up as high as they'd go (annoying the neighbours....opps) and the voltage bearly got past 12.95V....
Then after 2 more minutes idling the red light came back on......give me strength!
so i am now thinking that the springs on the brushes are not working hard enough....but they are sparking nicely at high revs and the light is still not going out.
thats it i'm having a break tonight and will play with the checks you've suggested in the morning.
do you think these latest symptons are getting us any closer to a diagnosis? _________________ '71 1302s with stock 1600 & 1982 T25 with 2.0 CU aircooled - living the dream |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15975 Location: North Florida, USA
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Posted: Fri Mar 09, 2012 8:42 pm Post subject: |
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Follow the link in my post above. Disconnect all wires from the generator and test as indicated by grounding the DF terminal for no more than a few seconds. Is your generator putting out decent voltage (see instructions in link)? You may need to raise the idle to get 30v+.
If the generator is good, suspect the VR.
Before doing any of this, clean all connections. Free way to improve voltage output. _________________ AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Choppski Samba Member
Joined: November 19, 2011 Posts: 53 Location: UK
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Posted: Sun Mar 18, 2012 4:00 pm Post subject: |
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Quick update - well i cleaned all the connections and voilą - the light went out.
could it really just be a bit of gunge causing this grief? Well, 5 days later and the dreaded light came back on.
so i went to the back and removed the dynamo bush cover and notices the top bush wasn't sparking at higher revs, while the bottom looks like bonfire night (an British version of 4th of July, in case you didn't know). so i put my finger on it and sparks flew....and the light went straight out.
now, i did have issues with the spring on changing the bush...i wonder if i damaged/ weakened it. are these generally available as i can't seem to find this as a spare very easily. is it really a dynamo job out? _________________ '71 1302s with stock 1600 & 1982 T25 with 2.0 CU aircooled - living the dream |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15975 Location: North Florida, USA
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Posted: Mon Mar 19, 2012 3:38 am Post subject: |
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I found this link:
http://gutsche.css-esales.de/index.php?sid=7ec0a04...A131903519 _________________ AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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