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Idiot Light

Discussion in 'Early CJ5 and CJ6 Tech' started by johnsotd, Jul 2, 2016.

  1. johnsotd

    johnsotd Member

    I know that this has been asked probably many times but I don't see it.
    My generator is showing charge at the regulator but the idiot light remains on.
    Something is obviously wrong but I don't know what.
    Your help is appreciated.

    1962 f-134 stock elec. system
     
    Last edited by a moderator: Jul 2, 2016
  2. eti engineer

    eti engineer Member

    How have you checked the gen output? Not trying to insult your intelligence. Just trying to get a starting point...
     
  3. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    What's the history on this? Has it started recently or has it always done it? Any recent electrical work done?

    H.
     
  4. johnsotd

    johnsotd Member

    Howard,
    I'm trying to re-wire to finish my build. I'm electrically ignorant and dumb.
    Wiring diagrams ( I have one blown up to nearly life size) look like all wires come from the same place on the ignition. (which wire goes to which post) The diagrams of the instrument cluster are only slightly clearer to me.
    This is my second build. The first one was done from scratch although I felt like I was buying fuses by the pound before everything finally fell into place....A large thanks to the forum. First build (V6, discs, dual MC, and Saginaw steering) has had no problems since completion.
    I have three FSM's but like I said I'm an electrical idiot.
    A local mechanic came by this morning and said I was charging at 14V at the gen. and regulator but did not know how to fix the idiot light.
    Thank you much.
     
  5. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Okiedoakie- you've probably got the light wired up wrong.​

    The light works by being bridged across the battery voltage & the the alternator/generator output- if the alt/gen isn't charging the alt/genn6y idiot light terminal is at "ground" level compared to the battery so current flows from your ignition terminal through the charge light to the alt/genny & through it's internal wiring to ground completing the circuit & causing the lamp to glow. When the alt/genny are working properly both ends of the light are at charging voltage so no current flows & the light doesn't light.

    You've probably got yours wired directly from battery voltage at the ignition to ground, this would put the light on any time the ignition is on.

    The charge light socket will have two terminals on it (& the shell of the socket is electrically isolated from the light bulb base), whereas "normal" sockets have one terminal (that connects to the bulb's center pin & the bulb base is grounded *through* the socket shell).

    The oil pressure lamp socket will be the same setup.

    First step- make sure you have the right bulb socket.

    2nd step-
    if a genny the second socket terminal connects to the regulator's armature terminal​

    if an alternator with external regulator (Motorola) it connects to the regulator "D+" (alt diode output) terminal​

    If an internally regulated alternator (delco 10/12 SI) there will be an idiot light terminal on on the alternator labelled "1".​

    3rd step- beer, Enjoy :)

    H.
     
    Glenn and 47v6 like this.
  6. johnsotd

    johnsotd Member

    Thank you.
    Since this post I have developed a starter issue ( see "starter disaster post" ). I will proceed as you suggest as soon as the starter issue is resolved.
    Thank you
     
  7. johnsotd

    johnsotd Member

    I did an out of the vehicle test and believe the generator is not genning. I think I will convert to an alternator with the built in regulator (10SI) and try to make my life simpler. I do, however, have a couple of questions that my search did not find.
    My belt is 5/8 v-groove. Should I run a narrower belt or look for a wider alternator pulley.
    I know that several of you have done this conversion and hope you will share your solutions.
    Thanks
     
  8. 1960willyscj5

    1960willyscj5 Well-Known Member

    My third step is Rum and Lemonaide.
     
  9. Glenn

    Glenn Kinda grumpy old man Staff Member

    Definitely wider pulley. Belts are supposed to run with the top at the top of the V, not down in the groove.
     
  10. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    " I think I will convert to an alternator with the built in regulator (10SI) and try to make my life simpler."

    Call me old-fashioned, but I don't see how anything can be much simpler than a generator.
     
  11. johnsotd

    johnsotd Member

    Pete, what should I look for to determine why my generator is not working.
    I have it on the bench now and can take it apart and work on it.
    Thanks
     
  12. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Check the brushes - that they are not worn out (too short), dirty, or sticking. Clean the copper commutator segments with solvent, polish with very fine grit sandpaper. Done.
    If the windings are shorted that will be a specialist job, but I've never seen it.

    Bearings can be replaced as needed.

    To generate, the regulator also needs to be working, and anytime it is disconnected it must be "polarized" with the generator when re-connected.
    Search here or the FSM for polarizing ("flashing") instructions, as it differs between types.
    Regulators are cheap to replace if necessary.
     
  13. Alan28

    Alan28 Well-Known Member 2022 Sponsor

    Electricity is subtle (except when you get a shock with the 220v, I had one recently) and some people understand it very well. And they are on this forum. Sometimes you believe that it is out of work, but in fact it works, but... when conditions are ok. On my Jeep it works, but I paid a specilist and I don't touch anything now. :n::(
     
  14. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Generators are simple in concept, but alternators are simple in their own way - and much more efficient. The semiconductor diode makes the alternator possible, and that's why we have generators only in very old cars. If you want to use an alternator, you can make it work. Wide groove pulleys for the alternator are widely available (pun intended) - wide belt alternator pulley - Bing There are plenty of articles about connecting an integrated alternator like the 10SI ... not difficult.
     
  15. Glenn

    Glenn Kinda grumpy old man Staff Member

    This is a very good write up. I especially like the description of how the idiot light works.
     
  16. Focker

    Focker That's a terrible idea...What time? Staff Member

    I agree with Glenn, great info.


    Oh...and I find it best starting with step #3.
     
  17. Glenn

    Glenn Kinda grumpy old man Staff Member

    Some times it is best to get that out of the way. :)