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'G' Warning light - Help, It's come on!

Discussion in 'Kombi Club' started by Harribo, Nov 5, 2013.

  1. Harribo

    Harribo Active Member

    Messages:
    309
    Location:
    Wollongong NSW
    Ps, where do I find the generator / alternator on a 2.0l engine so I can check for loose wires?
     
  2. Syncro27

    Syncro27 Well-Known Member

    Messages:
    6,605
    Location:
    Terrigal, NSW Central Coast

    A 15 minute drive should not cause any problems.

    Do you have a multimeter?

    If so check you battery - it should be about 12.5 volts with engine off and jump to around 13.5/ 14.0V when charging. Just put the black to black and the red to red on the battery terminals and see what you get.

    This will tell you if the generator or alternator is charging.

    I drove for about 1.5hrs with my alternator not working before everything died. Just dont switch anything on like wipers, headlights, indicators / brake lights etc (Ha! you will need the indictairs and brake lights).
     
  3. Dubman

    Dubman Well-Known Member

    Bingo - With my old Subaru a so called audio specialist wired up a hand picked system only for it to constantly cut out when turned to a volume suitable for human ears, anything lower say in an audible range suited to a dog was fine, took it to a mate who was a auto sparky, showed me the quality and rather small gauge of wiring used to power everything it was tiny, lets just say my speaker wires where a larger gauge than the power leads, swapped them to something heavier and designed for 12v current and what do you know it went past 11!!!! Rock and roll. needless to say my faith in "Audio" parts suppliers was lost. But thats not really helpful to Harribo (great gummie bears by the way)

    A large number of today's head units have a clock display that turns off when the car does etc and chew very minuscule amounts of current, in the 5+ years I have had a large somewhat fancy system in my bus the only time I had a flat battery was my fault.
     
    Last edited: Nov 6, 2013
  4. Dubman

    Dubman Well-Known Member

    Feel free to correct me if I'm wrong but years back when I had my Bug, I was told the generators need at least 80kmh for a period of time before any reasonable charging was to take affect, it was a while back and my recollection is vague, but I do remember not long after upgrading to an alternator and never having any grief. If it is the case then it could be the cause of the problem (That is if you have a generator over an alternator)
     
  5. chris taylor

    chris taylor Well-Known Member

    Messages:
    3,033
    Location:
    adelaide sth aust
    warning light

    The battery earth strap which is attached to the body should be checked at regular intervals as they can become covered in grime and therefore prevent proper earthing to take place which in turn will prevent a proper charging rate to the battery. I know this from personal experience { and very costly to}.A larger earth strap wont do any harm either.
     
  6. syncro

    syncro Well-Known Member

    Messages:
    10,246
    Location:
    Southern Highlands
    Some of them have difficulty in concentrating on breathing!

    Think about a new ignition switch. You may have a bit of resistance there. That will give an alternator light.
     
  7. syncro

    syncro Well-Known Member

    Messages:
    10,246
    Location:
    Southern Highlands
    That's correct, although 80kmh may be a bit high.

    If it is a 2L it will have an alternator.

    It may be worthwhile checking the conversion as it may have been done by a mechanic.
     
  8. saabman

    saabman Well-Known Member

    Messages:
    4,888
    Location:
    Goulburn
    Oops miss read one of your earlier posts.
     
  9. Abby.75

    Abby.75 Member

    Messages:
    291
    Location:
    Adelaide
    All else fails - pop into a real auto electrician rather than Autobarn


    A real auto electrician, for a VW doesn't exist... especially if you have anything remotely resembling Spaghetti under your dash. Most won't touch it and the rest charge a small fortune, and often aren't much good either.
    I've had the "G" light come on with my Bugs only... Never the Kombi.... once we drove home then to our mechanic (over an hour all up) with out any more damage than a regulator (you shouldn't drive the cae with thr generator light on....) also it could be the fanbelt causing the problem, so you should pull over anyway.... The other time I was told I could have started a fire....?
    Good luck with your problem
    Abby.75
     
    Last edited: Nov 6, 2013
  10. Marty

    Marty Active Member

    Messages:
    2,286
    Location:
    Sunny Melbourne
    Your sure it's not fur "Over G"? :lol:
     
  11. Harribo

    Harribo Active Member

    Messages:
    309
    Location:
    Wollongong NSW
    So I think it's the fact that I now have additional draw on the battery with the radio, it only comes on when I start the kombi but then as soon as I rev it up it goes out and doesn't come back on. Still going to get the radio taken off the ignition though as I want to listen to it occasionally without burning the coil or elec ignition out!
     
  12. REB

    REB Active Member

    Messages:
    359
    Location:
    sydney
    Get it rewired to a 12v connection to the battery so you can park and listen to radio without having keys in the ignition.
    You get use to having to turn it on and off yourself
     
  13. Dubman

    Dubman Well-Known Member

    On basic idle/choke mine is not charging either hence the light although in mine the G light is a battery, as soon as you cut the chokes (rev it a bit bang voltage increases and light goes off.
    Prob should have read the post a bit better sorry.

    My is a guess the alternator free wheels when warming up to save stress and once you load up and give the engine a push the alternator kicks in.
    again this is a guess Wheres Andrew when you need him (1500king) or even Nigel he loves that sort of stuff.
     
    Last edited: Nov 7, 2013
  14. saabman

    saabman Well-Known Member

    Messages:
    4,888
    Location:
    Goulburn
    An alternator works on the principle that an electric current is induced in a wire moving in a magnetic field.
    The faster the wire moves in relation to the field the greater the current is induced ( there is a point where losses become significant but that's for another day)

    The amount of voltage produced is determined by the speed of movement, the number of wires, and the strength of the magnetic field.

    I'll get on the computer shortly and continue rather than on the phone.
     
  15. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,634
    Location:
    Avalon Beach NSW
    It's the other thing that the fan belt runs around - ( other than the main flywheel. )
    2ltr engine will have an alternator.....bugger to check for loose wires 'cause they're encased in the alt. shroud, inside the rear of the unit .
    Alt. in/out is a fiddly, dick of a job best left for when you have a bit of spare time & patience !!

    Cheers, Mark
     
  16. saabman

    saabman Well-Known Member

    Messages:
    4,888
    Location:
    Goulburn
    The Alternator comprises of two main sections - the Stator (the windings that remain stationary around the outside) and the Rotor (the windings attached to the shaft with pully on that funily enough rotates)

    The magnetic field is created by applying voltage to the rotor windings. As the engine spins the rotor this creates a moving magnetic field which the Stator windings sit in. which consequently induces a voltage in the stator windings. Because the magnetic field is moving in a circle the out voltage changes levl and polarity (direction) - or Alternates.

    This alternating voltage is no good for much in a car so needs to be conerted to a single polarity (Direct Current) the diodes integrated in the alternator take care of this - just like a one way valve. They only let the current flow in one direction.
    [​IMG]

    If you have a look at the above picture you will see that there are actually three sets of windings in the stator and each winding has 3 diodes. 2 of the diodes (1b and 1C) convert the AC to DC which goes to charge the battery and run your lights etc. the 3rd diode 1a half wave rectifies the voltage produced in the stator and that voltage is used to provide the voltage to power the rotor and create the magnetic field. This is called self excitation.
    The regulator monitors the self excitation voltage (D+ Terminal) and adjusts the amount of current flowing through the Rotor winding which causes the magnetic field to change which adjusts the output voltage.

    To get the processs started when you turn the ignition switch on 12v is supplied to the stator winding through the Alternator Lamp the current through the lamp causes it to glow brightly.
    Once the alternator is going it produces its own excitation voltage and as D+ and B+(Battery +) outputs of the alternator should be at the same voltage. When that happens there is no voltage accross the globe and it goes out.

    For the Globe to come on when the engine is running either the D+ voltage has to be lower than the B+ Voltage (or Battery voltage) OR the B+ voltage has to be lower than the D+ voltage.

    If the brushes wear out the alternator wont producing anything so D+ will be 0v and current will flow through the globe and turn it on.

    In a Kombi it is rather easy to have the other situation occur. due to the long length of wire from the Battery to the ignition switch and to the G light - if you turn the headlights on and the wipers there will be a voltage drop on that long power cable so the iginion side of the Globe will be lower than the volatge on the D+ side of the globe and it will start to light up. You also need to consider the fuse holders as well - a bit of corosion on a fuse end will drive the resistance of the circuit up as well accentating the problem.

    Im a lousy teacher and explainer of things but I hope at least some of that makes sense.

    Im guessing that your head unit is connected to the top side of the 2nd fuse from right - which should be the fuse for the blinkers. Does the G light come on when you turn the blinkers on??
     
  17. saabman

    saabman Well-Known Member

    Messages:
    4,888
    Location:
    Goulburn
    The choke heater element runs all the time Nath (while the ignition is on) . (unless you phisically disconnect the wires )
     
  18. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,634
    Location:
    Avalon Beach NSW
    Hey Bernie, brilliant mate !! Great explanation ....never quite understood the term 'alternator' before...(sort of knew it charged the battery but that's all..:eek:)
    Cheers,
    Mark
     
  19. john doherty

    john doherty Well-Known Member

    Messages:
    795
    Location:
    adelaide
    I can't believe you just did all that Bernie, and you didn't even charge for it.
    What is even more scary….You did it in such a fashion that even I understood it.
    I am seriously in danger of learning technical information pertaining to the mechanical and electrical health of my ride…… I seriously need a drink!

    Yours in cyber wonderment
    JD in Adelaide
     
  20. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,634
    Location:
    Avalon Beach NSW
    Hey JD, if you're anything like me you'll read it, understand it, completely f*ck it up trying to explain to someone else...& then you'll forget it....:umm:
    Cheers, Mark
     

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