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voltage limiter wired with temp & fuel gauges

Discussion in 'Repairs, Maintenance, Help' started by Rico Rios, Dec 13, 2017.

  1. Rico Rios

    Rico Rios New Member

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    I had a mechanic install a new temp gauge , what I got was a blown temp & fuel gauge. I told them to replace the voltage limiter , which they did but I still don't have a working temp or fuel gauge. My question is "anyone know or have a picture of the back of the cluster that shows how the wiring goes from the voltage limiter to the gauges" ? I'm afraid they might have them wired wrong , I have two pictures of the back of two clusters both are 1970- 1974 cudas and challengers and they are wired differently. I really don't want to install two new gauges and have them wired wrong, I have already tested the voltage limiter and it is reading 12 volts going in and putting out 5 volts which should not be blowing the gauges. Any help would be greatly appreciated !!

    Thanks For Your Time,
    Rico
     
  2. Best Answer:
    Post #3 by AllanC, Dec 14, 2017
  3. 68RT

    68RT Well-Known Member

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    Look up Electrickery II in ALLPAR vintage repairs. Explains repair and how it works.
     
    Rico Rios likes this.
  4. AllanC

    AllanC Well-Known Member

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    This is a link to a diagram of instrument cluster wiring for a 1971 Dodge Challenger which I have enlarged and annotated with comments. Following the circuits should help in determining if the temperature gauge and fuel gauge are wired correctly.

    Dropbox - Dodge Challenger Instrument Wiring (at https://www.dropbox.com/sh/2spud2aibw5npka/AAC_XJZDyUA9m3rJmZJnnAOJa?dl=0 )


    Original diagram is at link http://www.mymopar.com/downloads/1971/71ChallengerB.JPG.

    The yellow trace is the 12 volt switched power feed from the ignition switch to the voltage limiter. On the diagram it is indicated as black but I used yellow for greater clarity. You indicate that you have 12 volts input to the limiter and 5 volts output. So you know that the voltage limiter is working.

    As outlined in the diagram I have identified the circuit (black trace) that provides 5 volt constant voltage to 1 terminal on the temperature gauge and 1 terminal on the fuel gauge. The diagram does not indicate color of the output wire from the voltage limiter; it might be black. The output of the fuel gauge goes to a connector with many other wires and then exits and travels under the body or under the carpeting to the rear of the vehicle and onto the tank sending unit. I have identified this circuit in the diagram with blue trace.

    The output of the temperature gauge identified as violet trace travels to the firewall and into the engine compartment and onto the engine temperature sending unit. It is possible that the input and output wires for each gauge are switched.
     
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  5. Rico Rios

    Rico Rios New Member

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  6. Rico Rios

    Rico Rios New Member

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    Thanks 68RT and Allanc for helping me out !! I really appreciate it guys Thanks Again !! Rico
     
  7. David Eidell

    David Eidell Well-Known Member

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    If I may make a suggestion -- without getting too technical.
    PS: This destroys the OEM vintage value of the car. Beware
    For a forever fix and much more accurate gauges, use a DC to DC voltage BUCKER. They are available on eBay. The dash gauges must be yanked and small wires soldered to the voltage limiter socket on the back of the PC board. This is not recommended for anyone but a tekkie that is into soldering and is willing to find out which side of the socket is input and output to the gauges. These buckers are not packaged with insulation in mind so that must be addressed as well. Is it worth it? It's a lot of work...
     
  8. Rico Rios

    Rico Rios New Member

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  9. Rico Rios

    Rico Rios New Member

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    AllanC Your diagram shows the Voltage Limiter with only 2 tabs mine has 3 one is for the condenser/ capacitor or whatever it is called. Your showing the ignition 12 volts connected to one tab and on the other tab next to it is the wire going to the fuel and temp gauges. Mine came back from the shop with the ignition 12 volts connected on one tab and on the other tab the capacitor is connected. On the 3rd tab opposite of the other 2 tabs is a wire connecting one wire to the fuel and one wire to the temp gauge ( like a pigtail connecting both gauges to the single tab ) am I making any sense ??? Your answer would be Greatly Appreciated !!

    Thanks For Your Time,

    Rico
     
  10. Rico Rios

    Rico Rios New Member

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    AllanC Your diagram shows the Voltage Limiter with only 2 tabs mine has 3 one is for the condenser/ capacitor or whatever it is called. Your showing the ignition 12 volts connected to one tab and on the other tab next to it is the wire going to the fuel and temp gauges. Mine came back from the shop with the ignition 12 volts connected on one tab and on the other tab the capacitor is connected. On the 3rd tab opposite of the other 2 tabs is a wire connecting one wire to the fuel and one wire to the temp gauge ( like a pigtail connecting both gauges to the single tab ) am I making any sense ??? Your answer would be Greatly Appreciated !!

    Thanks For Your Time,

    Rico
     
  11. AllanC

    AllanC Well-Known Member

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    What is the specific year and model car that is being discussed?

    Look at the 2 attached images. Which best illustrates the voltage limiter on your cluster: the 2 insulated terminal limiter or the 3 insulated terminal limiter?

    Voltage Limiter 2 Term.gif Voltage Limiter 3 Term.gif

    If the image of the voltage limiter with 3 insulated terminals is closest to that found on your cluster and it is wired as I have noted in the diagram, then it should be wired correctly at the limiter. However, the pulsed, constant 5 volt output wire from the voltage limiter still MUST BE ATTACHED to the proper terminal at the temperature gauge and fuel gauge.

    How is the voltage limiter case attached to the instrument cluster? Is there a metal case on the voltage limiter? The voltage limiter must be grounded through the case to the instrument cluster to function properly.
     
    #10 AllanC, Dec 16, 2017
    Last edited: Dec 16, 2017
  12. Rico Rios

    Rico Rios New Member

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    The 3 insulated terminal limiter is the one I have on my cluster (1973 Plymouth Barracuda). The voltage limiter is in a metal case and is grounded. I will test it tomorrow and will let you know.
    Thanks Again AllanC,
    Rico
     

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