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Battery not charging while running??

Discussion in '40- & 55-Series Tech' started by 78goode40, Apr 16, 2003.

  1. 78goode40

    78goode40

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    I've searched and read a few posts on this but still having trouble.
    I have replaced the alternator and voltage reg. (factory volt.reg.), but still no charge. I can get it started, but while running the volts just keep dropping. I have checked all grounds and they are very good. Alternator tests good.
    I spoke with a shop today and gave them the scoop. The guy I spoke with was somewhat familiar with cruisers (more so than most I have spoken to) He said that there is a "??charge light relay??" on inside of fender? which would cause a problem like this. Anyone have any advise or experience with this?

    Thanks to all in advance.
    Am I missing something obvious?
     
  2. Gumby

    Gumby Supamod Staff Member s-Moderator

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    I don't think the 40 uses a charge light relay. I don't have a wiring diagram in front on me though. Is there voltage to the field wire on the alt? Is there power to the voltage regulator?
     
  3. Pin_Head

    Pin_Head

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    Check for a bad connection in the B+ circuit (White with light blue stripe that runs through the ammeter and fusible link to the battery). This is often bad right at where it joins the battery + pole and if it is bad enough it won't run at all.

    Also put a volt meter on the B+ lug at the alternator and measure the voltage. If you only have 12V when running, then disconnect the two wire plug and momentarily jump a wire from the battery + to the F terminal and measure the voltage. If the voltage goes above 12V, then the alternator is good. If not, the alternator is bad or not grounded.
     
  4. aZ..fj-40

    aZ..fj-40

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    Hi, I had sort of the same problem, replaced the alternator (big mistake) and then found the B+ wire fried at the connector on the inside left fenderwell, Earl, AzFJ-40
     
  5. 78goode40

    78goode40

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    The two wire plug? If this is on inside of left fenderwell, the plug in harness is in bad shape. Very, very dirty and held together with electrical tape from previous owner. Looks pretty bad to me, being a rookie at this. Is there a fuse inside this connector, or is it possible to cut it off and just wire it together?

    I am getting power to the volt. reg.

    I have not checked the white/lightblue connection at battery, I will do so tonight when I get home.

    The previous owner half assed most everything he did to the 40. Used "wire nuts" for connections under the hood. Wouldn't this be good for getting water in it if submerged??
    Also, I've got a few household appliance power cords, cut and used for wiring.. hmmmmm interesting.
     
  6. woodsfj40

    woodsfj40

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    The previous owner of my 1968 FJ-40 did similar work to the electrical system. Fortunately the electrical system on a '68 is very simple. I just ripped EVERYTHING out and started over. Bought a few spools of different colored wire, some heat shrink waterproof connectors and splices. Took a weekend of my time, but I have 100% confidence in the cruisers electrical system now.
     
  7. Pin_Head

    Pin_Head

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    Don't confuse voltage with power. Just because you have 12V doesn't mean that it is flowing curent. When connections are corroded, the current doesn't flow.