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Amp meters, 79+ who has one that works?

Discussion in '40- & 55-Series Tech' started by Landpimp, Jan 14, 2004.

Does your 79+ fj40 amp meter work?

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  1. Landpimp

    Landpimp

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    As I have never seen one that works I figure its time to get polled(yeah it hurts a bit) I know both of my 82 amp meters dont work.
     
  2. Romer

    Romer fatherofdaughterofromer Moderator

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    Mine works in my 77. It shows the difference in load when I turn the heater on and off as well.

    Ken
     
  3. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    A very good customer/friend has a 12/82 40, I have been around the truck multiple times a year for maintenance or play, and have not ever noticed it not working properly...for what that is worth John.

    Good luck!

    -Steve
     
  4. Landpimp

    Landpimp

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    ummm, 79+ is not 77 :flipoff2: all my older amp meters works, just not the 82's.

    [quote author=romer link=board=1;threadid=10162;start=msg90742#msg90742 date=1074139048]
    Mine works in my 77. It shows the difference in load when I turn the heater on and off as well.

    Ken
    [/quote]
     
  5. Landpimp

    Landpimp

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    heck mine look like they work...... but just sits glued to the middle of the gauge ;) I'm sure some work. I think Rick D, told me neither of his 81's worked...

    [quote author=Poser link=board=1;threadid=10162;start=msg90748#msg90748 date=1074139280]
    A very good customer/friend has a 12/82 40, I have been around the truck multiple times a year for maintenance or play, and have not ever noticed it not working properly...for what that is worth John.

    Good luck!

    -Steve
    [/quote]
     
  6. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Ever put a clamp on amp meter on the output lead of the Alt. and turned on all acc. at high idle? Don't the '79's and on have a higher calibrated ammeter, which at lower current flow could be harder to notice?

    Just another idea..

    Good luck!

    -Steve
     
  7. IDave

    IDave

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    It's 50, like John said, as opposed to 30. But you'd still see it move if it were working. Now I am really curious as to why it wouldn't work. Gotta friend with a '83, I'll ask him.
     
  8. rick_d

    rick_d

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  9. crewzerdog

    crewzerdog

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    John, I don't "think" mine works because it basically stays static however it does 'flick' or twitch ever so slightly when I turn on some electrical gadget on the truck. I was told by a well versed cruiser mechanic that earlier trucks actually had trunk wires connected to the two poles (+ and -) on the back of the instrument cluster but as you know, the 79 cluster just has one main multi-wire plug on the back (actually has one small another connector to the cluster lights I believe). It does still have the + and - markings on the two ammeter posts but mine doesn't have any separate wires connected. The cruiser mechanic says he's seen some 79s with wires connected to these posts and one such cruiser supposedly wouldn't start without these wires reconnected. For mine and at least one other used wiring harness I bought - neither has any wires coming from the harness in this area and I traced the color coded wires from the alternator back to the dash area and they don't go to the cluster as best I can tell. So your guess is a good as mine. I think Steve may be on to something regarding the higher output alternators on the 79s.
    PS - thanks for the help on the overheating question.

    Tom
     
  10. Pin_Head

    Pin_Head

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    It is normal operation.

    They should just sit with the meter in the middle indicating zero current and you should see a flick when you turn on the headlights. This means that the alternator is working and the battery is charged. If you want to see what it looks like when the alternator isn't working, just disconnect the large B+ wire at the alternator and then run it with all the lights and accessories on. It should indicate about 30A discharge. When the battery has been drained and needs charging it will read 30-50A in the other direction and it will slowly drop to zero as the battery charges.
     
  11. 79fj40

    79fj40

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    I have a 79 and mine has not worked since I have owned it. I thought it was just mine.
     
  12. cruise4070

    cruise4070

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    My 82's doesnt work either. :'(
     
  13. Landpimp

    Landpimp

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    well mine don't move a c*nt hair........just sit in the middle.........can have everything on........don't move. my fj45 moves like I would assume it should.

    But I will try your test.

    I also recall you mention testing the gauge with a AA battery.........I didn't understand how this works?

    John


    [quote author=Pin_Head link=board=1;threadid=10162;start=msg91473#msg91473 date=1074391349]

    It is normal operation.

    They should just sit with the meter in the middle indicating zero current and you should see a flick when you turn on the headlights. This means that the alternator is working and the battery is charged. If you want to see what it looks like when the alternator isn't working, just disconnect the large B+ wire at the alternator and then run it with all the lights and accessories on. It should indicate about 30A discharge. When the battery has been drained and needs charging it will read 30-50A in the other direction and it will slowly drop to zero as the battery charges.
    [/quote]
     
  14. Pin_Head

    Pin_Head

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    [quote author=Landpimp link=board=1;threadid=10162;start=msg94682#msg94682 date=1074902254]
    well mine don't move a c*nt hair........just sit in the middle.........can have everything on........don't move. my fj45 moves like I would assume it should.

    But I will try your test.

    I also recall you mention testing the gauge with a AA battery.........I didn't understand how this works?

    John
    [/quote]

    When everything is working right, the meter should stay right in the middle, indicating zero. That is because it measures the NET current flow from the battery. When the battery is fully charged and the alternator is providing all the juice, these is no net current to the battery.

    The '79 up meter itself measures low currents of about 0.1 amp. Even a flashlight battery will peg it. If you remove one of the two fuses and connect the wire ends of the fuse holder to a flashlight battery, you will make a complete circuit through the meter and cause it to deflect fully. The current flows from the battery to the meter, back through the other fuse and fusible link to the other end of the battery.

    HTH
     
  15. sherwood

    sherwood

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    Mine works fine. Just a real minor flicker with everything on and the emergency flashers on. Of course it seemed to deflect more before I rerouted my new headlight/relay setup which now has it's own fuse and connects to + closer to the battery...... before the fusible link........ out of the ammeter loop.

    John Sherwood
    Charlotte, NC '79 FJ-40 TLCA Upstate Cruisers
     
  16. nasty habit

    nasty habit

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    Check the small wire at the fusible link area. If the connection is lost-no amp gauge. They usually take a hit from battery fungus. I think that wire is in the harness in 78 and up.
     
  17. Landpimp

    Landpimp

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    well i did the battery test, and guess what?............the guage peged to each side, depending on which fuse I pulled and hooked the battery up to. So I "guess" it works. Why is there such a range(50amp +-)
    if it really doesn't move much? But regardless...........thanks for the help testing it :)

    Guess i'll drain one of the batteries today and see what happens. Am I corect that if the batts never get below 12.6v then the guage won't move?
     
  18. alf

    alf

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    Mine appears to work 4/79 but never questioned it.

    alf
     
  19. Pin_Head

    Pin_Head

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    It is easier to just disconnect the B+ wire at the alternator to check it.

    If the gauge works, but doesn't read properly, the problem is the connection of the wires at the ends of the fusible link or a fusible link with incorrect resistance. If you look at the schematic diagram, the meter is in parallel with the fusible link, so they are parallel resistors. The resistance of the link is about 0.01 ohm, while the meter is about 10 ohm (or something like that). The system is sensitive to bad connections and the connections are near the battery where they tend to get corroded.
     
  20. Landpimp

    Landpimp

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    yeah but I can run outside in my boxers and turn the lights on, come back inside and wait for the cook for finish breakfast :D

    I did have to remake the fusible links when I bought the 40(as you can get new anymore) I think I used 14 or 16 guage link wire. Beside the gauge(of wire) would the length of the wire be an issue?

    to be honest Ohms are a mystry to me(seeing how I lost the manual for my meter I can't figure out which holes to use on the meter ::) even though I went to school with a grandsons of Mr Ohm.......no kiddin. Also in the same class was the grandsons of the guy who wrote the Troll books.........damn what are they called, ah the Bothers Grim, wierd kids. And Kurt Vonagets granddaughter.......she was hot BTW :)

    Still waiting for breakfast ;)

    John H

    [quote author=Pin_Head link=board=1;threadid=10162;start=msg95221#msg95221 date=1075054811]

    It is easier to just disconnect the B+ wire at the alternator to check it.

    If the gauge works, but doesn't read properly, the problem is the connection of the wires at the ends of the fusible link or a fusible link with incorrect resistance. If you look at the schematic diagram, the meter is in parallel with the fusible link, so they are parallel resistors. The resistance of the link is about 0.01 ohm, while the meter is about 10 ohm (or something like that). The system is sensitive to bad connections and the connections are near the battery where they tend to get corroded.
    [/quote]