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Early A-Body Discussions

  1. gsoco

    gsoco gsoco

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    Hello again guys. I got my 62 Valiant running but now the gauges are pegged - fuel - pegged low and water temp pegged high - ammeter seems OK... No panel lights - once in awhile I get a backlight to go on (new switch installed) wipers work... Thought the instrument cluster voltage limiter might be the culprit...any ideas? Tired of laying on my back in 90 degree heat and trying to fit my meat hooks inside the dash:mad: I'd like to fix this once and for all. Any thoughts / help is much appreciated.
    Cheers,
    Jason
     
  2. 66jim

    66jim Well-Known Member

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    Hows the Oil pressure gauge? If that OK then the instrument voltage regulator is
    Ok. That being said the other 2 gauges first need to be checked as separate problems. Lift the wire from temp sender and measure from that wire to chassis ground It should be 5V ditto the fuel. If this checks out sounds as if the temp wire or sender
    is shorted to ground and fuel sender is open
    Panel lights could be bulbs or no 12v to circuit board, also remove the electrical
    socket(multi wire) on the back of the instrument cluster to clean and inspect.
     
  3. gsoco

    gsoco gsoco

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    Thanks. Have 12V to ammeter / ignition sw. No oil pressure gauge....just idiot light. "Gauges" are ammeter (C---/---D), fuel(E-------F) and water temp....(C-------H)....new panel bulbs....also, no headlights....all fuses replaced and new switch...will post more after testing tomorrow. Thanks again.
     
  4. Mattax

    Mattax Just the facts, ma'am FABO Gold Member

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    Ammeter is not related to the others.
    It shows current in or out of the battery. Be super careful working all of the main wires since they all connect to the battery! On '62 I don't beleive there is even a fusible link. So if you ground anything in that circuit it will be welding!

    The main circuit looks something like this, except no fusible link:
    upload_2019-6-8_19-26-17.png


    The other gages have sending units and probably work from the instrument voltage regulator.
    They get power from the either the key switch direct or key switch through the fusebox. Then they are probably regulated to 5 volts at the instrument panel.

    The '63 up instrument operation explained in detail in this Chrysler booklet.
    Electrical Diagnosis (Session 185) from the Master Technician's Service Conference
    But '62 could be different. Someone here should know if you dont have a shop manual.
     
  5. gsoco

    gsoco gsoco

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    I do have shop manual....and use it. Question...my new ignition sw.had a grand pole that doesn't connect to the Wi-Fi.g harness plug. Should I ground it?
     
  6. Mattax

    Mattax Just the facts, ma'am FABO Gold Member

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    Might be a generic ignition switch. I've not seen anything in the shop manuals where the switch needs or could even make use of a ground. Maybe 62 is different I can't thiunk of what might need a ground. The switch is power in, then ignition 1 & accessory terminals get connected when in key is in Run
    ignition 2 and starter relay terminals get connected when key is in Start.

    I'm assuming Wi-Fig is a phone correction LOL
     
  7. RedFish

    RedFish Well-Known Member

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    Everything one these old cars relies on nut and bolt metal to metal for ground path. Inst' panel is no exception. If it isn't screwed to the dash, the lighting, etc., will not work.
    A aftermarket replacement headlight switch will also have a terminal for ground wire that OEM switch does not have. Adding these ground wires is not absolutely necessary but... if the switch is mounted in the same metal housing the added wire provides additional ground path to entire metal housing.
    Temp gauge pegged to H has often been that purple sender wire pinched under a valve cover or otherwise shorted to ground in engine bay. Fuel gauge needle moves only from home to E at switch on has often been saturated float.
    I would take the inst' panel to the workbench. A 12 volt power supply will test all lighting. A 3 volt battery/power supply will test fuel and temp gauges to about 1/2 their range. If it all works at workbench it should work in the vehicle.
    Your gauge voltage limiter? I don't know if 62 had the plugged in can type. It might be in the fuel gauge or in the temp gauge. If it is in a gauge that gauge will have 3 posts.
    We'll assume it is working because the gauges are working.
    While the inst' panel is out of the car, temp gauge is purple wire, fuel gauge is dark blue. Check ohms signal from senders on both these. 80 is fuel E and temp C , 10 is fuel F and temp H.
     
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    • gsoco

      gsoco gsoco

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      Wow! Great information. Thanks. Will do...heading to the garage...:elmer:
       
    • gsoco

      gsoco gsoco

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      OK..yes it was supposed to say "wiring harness" plug....:BangHead:
       
    • gsoco

      gsoco gsoco

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      OK. I think I am f&^%ed...I now have 24 VDC at the battery and the rest of the dash is dead. Not sure what I did (fried the ammeter?), but that's where I am now - how did I get 24 volts at the battery?? I am lost.
       
    • Mattax

      Mattax Just the facts, ma'am FABO Gold Member

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      Lets step back and see if we can understand what is you have and what is going on.
      If you can take a photo of the '62 engine and inteiror wiring diagrams from the FSM it will help us see what differences with '62.

      Stock wiring?
      Are there any electrical items added or alternations?
      With what are you measuring the voltage? Could it be a setting on the meter? Scaling or zero function?

      The ammeter is basically a big fat metal plate with a little parallel circuit which moves the needle to show discharge or charge. For example engine off, dome light on, you'll see a small amount of discharge on the needle.
      High voltage alone shouldn't damage it. Excess current through it can melt things depending on how much current, for how long, and how that particular meter is constructed. If you see it pegged either direction - that's too much!
       
    • gsoco

      gsoco gsoco

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      Lets step back and see if we can understand what is you have and what is going on.
      If you can take a photo of the '62 engine and inteiror wiring diagrams from the FSM it will help us see what differences with '62. Send me an email address (If allowed) and I will email the FSM drawings... otherwise I will take a photo...

      Stock wiring? YES
      Are there any electrical items added or alternations? NO
      With what are you measuring the voltage? Could it be a setting on the meter? Scaling or zero function? DIGITAL MULTIMETER...pretty sure the settings are correct...

      The ammeter is basically a big fat metal plate with a little parallel circuit which moves the needle to show discharge or charge. For example engine off, dome light on, you'll see a small amount of discharge on the needle. Before I lost everything, this was the case...now all is dead. Zero volts anywhere inside the car...
      High voltage alone shouldn't damage it. Excess current through it can melt things depending on how much current, for how long, and how that particular meter is constructed. If you see it pegged either direction - that's too much! Roger...I tried to insert a voltage limiter.
       
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      • gsoco

        gsoco gsoco

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        62 Valiant body wiring diagram.jpg 62 valiant inst panel wiring.jpg 62 valiant engine wiring.jpg
        OK - was able to get these as a .jpg...thanks so much for all your patience and help...
         
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        • Mattax

          Mattax Just the facts, ma'am FABO Gold Member

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          If I'm reading correctly there may be an instrument voltage limiter in the temperature gage.

          There's some guys here who were or are techs that know more about the different digitial meters.

          My suggestion for now is to start checking voltage to ground starting at the battery.
          In other words.
          Disconnect the battery and check its voltage. This will should either restore confidence in the meter readings or not.
          Then reconnect the positive and ground cables and check the voltage at
          the big starter stud
          then at the starter relay
          then probe the firewall disconnect terminal for Q1
          Now you can jump ahead while your there and check the terminal for R6 as well.
          Both should be at battery voltage.

          If there's voltage at Q1 and not at R6, there's break inside. Find the next terminal that's exposed and reasonably reachable and see it has voltage. Probbaly inside of the bulkhead connector, then each of the ammeter studs or key switch if that's easier.
           
        • gsoco

          gsoco gsoco

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          OK. Tomorrow's plan...Thanks.
           
        • RedFish

          RedFish Well-Known Member

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          You didn't say what happened. We should assume sparks flew? This is why so many service procedures begin with "disconnect battery cable". Maybe your amp gauge served as fusible link.
           
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          • gsoco

            gsoco gsoco

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            There were sparks then nothing... so amp gauge is probably OOC...? Test method?
             
            Last edited: Jun 10, 2019
          • gsoco

            gsoco gsoco

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            The battery still reads 27 VDC across the poles. I am going to where I purchased it to have it tested / replaced before I do anything else stupid...OK - back with new battery...so any testing I should do with battery disconnected?
             
            Last edited: Jun 10, 2019
          • RedFish

            RedFish Well-Known Member

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            I don't know. For most of us a serious short burns a fusible link open. Someone states that your model doesn't have a fusible link. Again I don't know.
            If everything inside the car is dead, there is a failure wherever the weakest link is. That should be the fusible link but... Maybe in your case the amp gauge shunt is the weakest link. I would imagine terminals in bulkhead connector would be weaker but again... I don't know. Good luck with it.
             
          • gsoco

            gsoco gsoco

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            OK. Thanks for your help.
             
          • Mattax

            Mattax Just the facts, ma'am FABO Gold Member

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            First check your meter. Grab another battery to compare 'cause its pretty impossible to increase voltage in a battery. Any good battery. Just see if its ballpark correct.
            Ruh oh!
            Well something burned through or melted. The question is what.

            First thing is get make sure your multimeter is working.
            Then you can seek out the circuit break as I suggested last night, or instead use a test light with the same method. Start at the battery and check at each accessible point in the circuit.
            You could also look for continuity by leaving the battery disconnected and using the ohmmeter function.
             
            Last edited: Jun 10, 2019
          • Mattax

            Mattax Just the facts, ma'am FABO Gold Member

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            The jpg from the FSMs are hard to read due to the way FABO reduced the image. But there's no fusible link shown.

            Some ammeter's are more robust than others. If the sparks flew from the ammeter's battery post, then no current when through the meter. If the sparks flew from the other side, then it could have been damaged. But like Redfish said, there's no way to guess that. The ones that fail usually do so 'cause they got hot enough the plastic distorted allowing the connections to loosen. Yours might not even be made of plastic.

            Anyway here's my current interpretation of the '62 main circuit.
            There should be no break in the these wires.
            In other words when the battery is hooked up these should be at battery voltage.
            upload_2019-6-10_10-58-40.png
             
          • gsoco

            gsoco gsoco

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            Ok. On it. Thanks!
             
          • gsoco

            gsoco gsoco

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            OK. Power to ignition switch, but won't crank. Jumping it across the starter cranks, but now won't start....ballast resistor is frying....
             
          • Mattax

            Mattax Just the facts, ma'am FABO Gold Member

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            Slow down!
            One step at time. There's a problem in there or several. Trying to jump ahead and start the car before figuring it could create more trouble.
            What do you mean there's power at the switch?
            Are you using a meter or a test light?
            What voltage is at the battery?
             
            Last edited: Jun 10, 2019
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