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Temp Gauge Anomaly

Discussion in 'Early CJ5 and CJ6 Tech' started by browncoat, Mar 14, 2018.

  1. Mar 14, 2018
    browncoat

    browncoat Member

    Maitland Australia
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    Also posted this question in my build thread but was suggested it might get more views if asked elsewhere so here goes.



    I can't get the temp gauge on a brand new speedo unit to work at all no matter what I try.

    The fuel gauge works fine but when the power is applied to the fuel gauge post the temp gauge marker swings back up and left away from the gauge face and disappears behind the main speedo plate.:shrug:

    Normal position.Unpowered
    [​IMG]


    When power is put in to fuel gauge post.
    [​IMG]
    Marker goes into hiding.
    Moves fast, not the steady pace that the fuel marker moves to its level position, temp marker flicks back to the left instantly.

    At first I thought it was a dud gauge, even though it is a brand new unit it is only a cheapy. (Omix)

    So I got a replacement set of fuel and temp to replace both, but get the same reaction.

    To cover all the possible theories;
    The earth / grounding is perfect for both the speedo body and the fuel sender
    The temp sender unit is brand new and working, with resistance that drops as the engine eats up.
    Even earthing the sender post on the gauge to simulate hot temp /low resistance has no reaction to the marker dial, it stays hidden up to the left.

    Any idea's or suggestions appreciated.
    Thanks
     
  2. Mar 14, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    If I understand both gauges, the original & the replacement do the same thing.

    Can you take a pic of the innards of the original?
     
  3. Mar 15, 2018
    browncoat

    browncoat Member

    Maitland Australia
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    Hi Howard, both the original and the replacement are the same type and vintage.
    Both are brand spanking new and should be trouble free.

    The fuel gauge works perfectly, only the temperature gauge is acting weird.


    [​IMG]
    [​IMG]

    Bought the speedo and the replacement gauges from Morris 4X4
    Omix Speedometer Cluster Assembly, 0-140 Kph
    Omix Fuel and Temperature Gauges, Black - Pair

    Have an enquiry in with them as well to check if there are any QA issues with these gauges lately.
     
  4. Mar 15, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    OK that's not an "original design" type of gauge mechanism, looks lie an electronic "improvement". That explains the immediate needle movement, the old style gauges just don't move that fast.

    Sorry, no advice other than to see what Morris has to say, I'm guessing a manufacturing fault. :(
     
  5. Mar 15, 2018
    baldjosh

    baldjosh Member

    pacific north west
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    Oct 24, 2017
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    youre saying applying power to the fuel gauge effects the temp gauge...seperate units but both attached to the speedo...have you tried hooking up both temp and fuel when not installed in the speedo?...just thinkin out loud
     
  6. Mar 15, 2018
    browncoat

    browncoat Member

    Maitland Australia
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    Yep, the temp gauge gets its power via the fuel gauge.
    That's the standard procedure for the CJ gauges.

    I believe they need to be grounded through the speedo body to work properly, but I can give it a try.
     
  7. Mar 15, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    You'll certainly need to ground the cases back to your power source for them to work. On the original style gauges an improper ground will smoke them, can't say for sure about these.
     
  8. Mar 15, 2018
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

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    in 1991 I repaired the non working, stock gas and temp gauge on my 77 cj5. I went to the jeep dealer, got the "right" gauges and they were still wrong. I finally got it all to work, but it was a real pita. I hate when things don't work right, but honestly I would go separate gauges now and forget about the ones integral to the speedo. That being said, you bought new and it should work as advertised.
     
  9. Mar 15, 2018
    browncoat

    browncoat Member

    Maitland Australia
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    Have got Morris 4X4 customer service checking back to the manufacturer about the issue.
    The shipping cost to get the new gauges here to Australia was more than the cost of the gauges themselves so it has been an expensive exercise.

    Thankfully Morris 4X4 have been great when I had a problem with some warn hubs a few months ago, so I am hopeful they will help out with a solution or a refund.
     
  10. Mar 15, 2018
    Alan28

    Alan28 Well-Known Member 2022 Sponsor

    Châtillon en...
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    Sorry for your problem.
    I also bought a speedometer with gauges temp and gas but after some wasted time and energy I have an inependant temp gauge for willys, a oil pressure also for willys and concerning the fuel gauge, I wait for an other solution.
    These systems are very subtle and fragile, I am not clever enough so I took the solution of independant gauges.
    But of course I envy people with all informations working well in their beautiful speedometer.
     
  11. Mar 15, 2018
    baldjosh

    baldjosh Member

    pacific north west
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    just trying to understand...if power is supplied from the same source and both have a common ground wouldnt the temp gauge then just read the fuel tank sender or some verion of it based on the voltage input required to move the gauge x degrees?
    I gotta be missing something in my brain...
     
  12. Mar 15, 2018
    browncoat

    browncoat Member

    Maitland Australia
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    Will try to clarify but hopefully if I get it wrong someone will correct me.:bash:


    The power to both gauges is wired in series, so the 12v power comes to the fuel gauge first.
    That fuel gauge then reads the voltage resistance coming from the fuel sender and positions the dial relative to that resistance reading.

    Then one of 2 things happens depending on the age of the gauge.
    If it is an old original style unit the power is reduced inside the fuel gauge down to around 5V and sent via a short wire to the temp gauge, where again the temp sender is supposed to read the resistance and position the marker in the appropriate spot.



    The newer gauges that I am having issues with seem to be direct 12V to both gauges out of the fuel gauge.
    Both the first and second gauges that I have purchased as brand new items have 12V going to the temp gauge via that short wire from the fuel gauge so I presume it is right.

    That is something I am having checked on, but the newer gauges seem to have eliminated the 5v idea.
    But the principle is the same apart from the volt reduction that happens in the older gauges.
     
  13. Mar 15, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    The gas &temp gauges are tied together, the instrument voltage regulator is actually in the gas gauge.

    Fuel gauge literally burned
     
  14. Mar 20, 2018
    browncoat

    browncoat Member

    Maitland Australia
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    Update on the temp gauge issue.

    Factory screw up.


    Actual email text.
    Depending on how old his gauge is (6 months or so) there was a wiring problem with the temp gauge. The temp gauge was wired in reverse. To correct, the wire from the 'A' terminal on the Fuel Gauge needed to go to the 'S' terminal of the Temp gauge. The temp sending unit would then go to the 'A' terminal of the temp gauge.

    Then it worked.

    [​IMG]

    So if anyone buys an Omix brand temp gauge in the future and it doesn't work, this might be why.
     
    47v6 and ITLKSEZ like this.
  15. Mar 20, 2018
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

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    Wow. They made it wrong and its your job to figure it out.. Thats not cool.
     
  16. Mar 20, 2018
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    DC Electric current flow = external is + to - and internal is - to +. Internal is direction you see inside the battery. In earlier years the Europeans favored positive ground which caused problems here with the imports.
     
  17. Mar 20, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    YES!!!

    [​IMG]

    :banana::banana::banana::banana::banana::banana::banana::banana::banana::banana:
     
  18. May 18, 2020
    Ducatichip

    Ducatichip New Member

    Tampa, FL
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    Glad that I found this thread. I spent two days trying to figure out why the temp gauge within the speedo wouldn't work (bought the Omix fuel/temp gauge replacement combo). Swapped the power and sensor wires/posts and waddya know, it works! Who would have thought that these would be wired backwards. Morris4X4 should put this in their downloadable instructions.
     
    Walt Couch likes this.
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