BYPASS the AMMETER? (1969 A12)

Electrical & Ignition

  1. WM23M9

    WM23M9 FBBO Gold Member FBBO Gold Member

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    So, since recently GUTTING all dash & engine wiring due to 50 years of whatever my father did or didnt do with this A12 Super Bee, I'm now seeing owners talk of NOT using the factory Ammeter? (69 Coronet 440 Six Pack, RALLYE dash).
    Personally? Never had a real problem with one out of the 20+ MoPars I've owned. Doesn't mean I won't though.
    Especially after the Glory of R&R all of this wiring. At 50 yrs old, the old on your back on the floorboard thing is not so easily done. Just regret it later.
    Any one else have a legitimate reason they'd NOT hook up the OEM ammeter when replacing a dash harness? (And engine harness?). Mine seemed to "read" like they always do, needle flops around the middle of "12V" it actually WARNED me after a few HARD street Drag Races on 7/13/2020 vs my buddy's 68 SS396 Camaro. ( He has YET, to pass my A12).
    Thoughts??? (Pic for entertainment purposes only).
    Most know exactly which CABLE that is.
    20200719_185305.jpg
     
  2. Durandal25

    Durandal25 FBBO Gold Member FBBO Gold Member

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    Geeeze.....that bulkhead connector looks roached out already. I agree with you though. As long as you power requirements don’t go past standard specs you should be ok. New harness is always a good idea
     
    Last edited: Jul 21, 2020
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  3. Ray70Chrg

    Ray70Chrg Well-Known Member

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    Got my project car 4 1/2 years ago. In researching other electrical problems, I found out this ammeter wiring could possibly cause you a lot of trouble. I never thought the ammeter gave you useful information anyway and would rather have a voltmeter instead. So rather than taking a chance on my dashboard going up in flames I bypassed the ammeter and have one less thing to worry about. Imagine how you would feel if this happened to your car AND you knew this was a possibility. Some day I'll have a voltmeter giving me useful info.
     
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  4. Durandal25

    Durandal25 FBBO Gold Member FBBO Gold Member

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    ....I also added a batter disconnect and had a fire extinguisher in the car at all times. Had 4 mopars and all four had the ammeter.....no scorch marks, but I did burn out a few fuse links over the years.
     
  5. tonysrt

    tonysrt Well-Known Member

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    The good thing about the Ampmeter is that it tells you when the battery is fully charged and not taking in any more amps. The voltmeter just tells that there is a certain amount of volts at the battery. Both have a good side in the circuit.
     
  6. twecomm

    twecomm FBBO Gold Member FBBO Gold Member

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    IMHO.. I believe that the alt, or amp meter, shows quite accurately whats going on with the cars charging system well beyond what a volt meter would. If your bulkhead connector happens to look anything like that picture posted, I would replace all associated with the bulkhead connector shell and contacts. If you don't, you might want to carry a few fire ext's. You just can't have funky corroded weathered contacts and expect everything to be trouble free. Also very important that the connections to the amp meter are in good condition and properly tight. What was designed into these cars electrical system, wire sizes ect. was designed to deal with what the car originally came with. Changing to different alternators, adding other electrical items require considering how the changes would effect the cars electrical system and what the additional current draw will have on existing wiring. 50 years takes it's toll...
     
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  7. Don Frelier

    Don Frelier FBBO Gold Member FBBO Gold Member

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    I'll take an ammeter any day, I agree with twecomm
    An A12 should be kept as original as possible (I think).
    A few things that might help you down the road, after you get the bulkhead situation repaired:
    1. If you still have the original gear reduction starter, change it for a permanent magnet like a Dakota or Mopar mini-starter. Save the original if thats what's in it.
    - it will crank over more quickly and start quicker so less drain on your battery
    2. Try to always start with a fully charged battery using a battery charger
    - The bulkhead melts when you have high charging current from the alternator
    3. Do everything tuning wise to make sure it starts quickly.

    4. Consider switching to LED or other low amperage headlights.

    Good luck with it.
     
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  8. 747mopar

    747mopar Well-Known Member

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    Ammeters need ALL of the amps going through them to be accurate, voltmeter's can be spliced in just about anywhere.. pretty big difference. I'm not old enough to know the story on these cars back in the day but it seems a lot of the fire issues are on aged cars??? If your keeping it bypass the terminals at the bulkhead and go straight through with quality wire, that alone should take care of the issue. Personally I like Voltmeter's, they're safer and give you more useful information. When my alternator takes a shit or my belt flies off I can watch my volts and keep on driving able to gauge how far I'll make it.
     
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  9. Don Frelier

    Don Frelier FBBO Gold Member FBBO Gold Member

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    I've had around 20 mopars over the years, worked on way more than that.
    I can only recall replacing 2 alternators, never had a belt fly off.
     
  10. super-bee_ski

    super-bee_ski FBBO Gold Member FBBO Gold Member

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    Do the MOD
    By pass the Ammeter...
    Better to be safe than sorry....
     
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  11. Nacho-RT74

    Nacho-RT74 FBBO Gold Member FBBO Gold Member

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    no need for bypass the ammeter, just make a path surrounding the bulkhead, upgrade your alt with one able to feed 50-55 iddling ( 45 is good too but more, better ) and you'll be done

    http://www.dodgecharger.com/forum/index.php/topic,33574.0/all.html

    You just need to UNDERSTAND how it works and how to read the ammeter ( most ppl doesn't understand the gauge ). If your car got constant Charge and Discharge reading your charging system is unbalanced. Don't worry, maybe is not your fault. The first fail came from factory really installing underrated alternators. Ppl tipically thinks a Charge reading is good, which IS NOT. The correct ammeter reading should be 0 the most time as posible

    ammeter-zero-master-tech1960-png.png

    AND NEVER SOURCE ANYTHING FROM BATT... EVERYTHING on the car with ammeter must be on alt side of the game. If your source added accesories from batt post, the ammeter will be stressed reading Charge which is not, but actually sourcing whatever is on batt post. Then ppl blames the ammeter and when melting everywhere


    Check ammeter for tigh studs. If loosen just add some lead to get it fixed with shunt, and new amm isolators if the existant are cracked ( one on each side of the cluster, two in total )

    https://premiumdashdecals.com/shop/dodge/dart/dart-demon/all-car-lines-ammeter-insulator/

    Myself in your shoes, would rebuilt the bulkhead ( which is available, don't need to replace the harnesses, just fix what is damaged ), new terminals, then add a parallel path.

    I have run my Charger FOR YEARS ( being driver ) with AC with the parallel path using an 80s 78 amp alternator. My amm is most of the time steady centered. Ammeter is cool, same as wiring.


    there is not a more accurate gauge for the Charging system than an ammeter. The Voltimeter is good too, but sometimes is not an straight reading of the Charging status.

    As an example, once I was getting a discharge reading on ammeter and a 18 volts reading on a voltimeter, and removing the batt wire, the engine stalled. Which it was the accurate reading ?

    You change tires, brake pads, spark plugs and wires, make mantenience on carburator, upgraded coil, body and paint job... why not make the propper mantenience on electrical too?
     
    Last edited: Jul 21, 2020
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  12. super-bee_ski

    super-bee_ski FBBO Gold Member FBBO Gold Member

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    Hmmm,
    I would follow 99.999% of the rest of the Forum and BYPASS the Ammeter....
    And:
    It's not like you are doing drastic mods...it's still original
    REMEMBER: Chrysler saw the issue and eliminated the Ammeter....
    They know best!
     
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  13. Nacho-RT74

    Nacho-RT74 FBBO Gold Member FBBO Gold Member

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    ammeter was eliminated because wasn't cost effective. Is so true than even on laters 80s and 90s models there was not even voltimeters but just an idiot light ( to make it even cheaper ). Need to say they changed to a shunted ammeter system on 75 ( 76 on A bodies ) which is a more expensive than the full load ammeter. In fact, M bodies got the shunted ammeter with a circuit board and an extra voltage test light.

    You can be disagree all that you want, But I'm able to proove the ammeter is the best way to know the actual status of the charging system and how to run it safe. But that will work just if you care. If you don't care to learn about it, then won't be the way to show that, no matter what I'm able to say.
     
    Last edited: Jul 22, 2020
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  14. Nacho-RT74

    Nacho-RT74 FBBO Gold Member FBBO Gold Member

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    BTW, the picture attached about the ammeter function ( zero reading ) is from Chrysler literature. Then after that it comes the various mistakes made along the years with our cars:
    -lack of power alternators from factory
    -added accesories to batt post
    -bigger capacity batts keeping same alt ( it should be the other way around ), taking FOREVER to get recharged the batt, so, more stress to the system.

    and there is one mistake what made everybody never understand the ammeter, which is being labeled as an ALTERNATOR gauge where is really a BATTERY gauge. If you get an ALTERNATOR being Discharged, get worried, because an alternator can't be discharged since is not an acumulator so it can't storage power. It sources or doesn't, but never get discharged
     
    Last edited: Jul 21, 2020
  15. WM23M9

    WM23M9 FBBO Gold Member FBBO Gold Member

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    Haha.....Yeah, pretty fried.
    I dont run anything but engine. Cant hear a radio over it anyway..lol
     
  16. funknut

    funknut Well-Known Member

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    If you want to keep it for originality then there's nothing wrong with the original design if you are not increasing power requirements. The problems start when connections get old and crusty and the resistance goes up which creates heat, which melts things, as you've already discovered.

    If you've replaced the wiring that needed replacing, nothing wrong with running an ammeter.
     
  17. Ranger16

    Ranger16 Well-Known Member

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    I was having some drivability problems with my '69 Road Runner. First the tach started occasionally jumping erratically. Then it started a random and occasional misfire. It got worse, to the point of being undriveable. I finally found an insulator on the ammeter that had deteriorated. I fabricated a new one and installed it. When I turned the key to start it, it immediately fried the fusible link at the bulk head. Thank God it was there. I then realized that there was another insulator inside the gauge. That was enough for me. I pulled both wires off of the ammeter and used a screw and nut to secure the two wires together and then insulated it with electrical tape. Haven't had a problem (or worry) since. The volt meter hanging under the dash is sufficient for me.
     
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  18. Nacho-RT74

    Nacho-RT74 FBBO Gold Member FBBO Gold Member

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    Don’t blame the ammeter, blame the unknowledgement! As usual

    BTW! The ammeter is a direct battery conection. Nothing related with ammeter would melt with ignition switch per your description. Fuse link would blown up as soon you conect the batt if any of both insulations get damaged.
     
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  19. metaldad

    metaldad Well-Known Member

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    ..........
     
    Last edited: Jul 23, 2020
  20. Ranger16

    Ranger16 Well-Known Member

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    I stand corrected. It DID fry the fusible link when I connected the battery, NOT tried to start it. My apology for the misinformation.
     
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