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Temperature Gauge No Workie

Discussion in 'Early CJ5 and CJ6 Tech' started by CJ51973, Apr 22, 2022.

  1. Apr 22, 2022
    CJ51973

    CJ51973 Member

    Versailles, KY
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    So I am on my second set of gauges. Yes, Omix. I took out the first fuel gauge when my sender grounded out. It is the gauge, not the sender. I tried a resistor and it won’t move. Some numbers. Sender is 2K ohms at 70 degrees, seems fair. The gauge is 230 ohms A to S, not the 20 ohms I think it should be. I will not buy another gauge unless I know for sure it’s not Omix. Anything I am missing? The fuel gauge works btw. Thanks
     
  2. Apr 22, 2022
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    Why do you think that 2000 ohms is right for the sender? Where are you getting the numbers for resistance through the gauge? That's not in the TSM, that I can see. 2000 ohms is about 100x what the reading should be for the sender.

    Do you measure any resistance through the gauge? A to S should be the fuel gauge. The TSM says the temperature gauge has an I and an S. Which manual are you reading?

    Jeep1972Gauges (442 x 360).jpg

    This is from the '72 TSM. I on the fuel gauge is the pulser input (12V), and A is the pulser output (5V time averaged).

    The '74 TSM is free to read and download on the Tom Collins site. All this will be the same for '71, 73, or '74. I kinda have to assume this is the '71 you're working on, since it's in the early forum. Suggest you read chapter 3 from the '74 manual and follow the diagnostic flow charts there.
     
    Last edited: Apr 22, 2022
    Ol Fogie likes this.
  3. Apr 22, 2022
    CJ51973

    CJ51973 Member

    Versailles, KY
    Joined:
    Nov 6, 2009
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    116
    Got the 5 volt pulse. Got 230 ohms between the two post on the temperature gauge with nothing attached. I see “high resistance “ at cool temperatures on the sending unit. Do you have this number? What it should be cold? If I disconnect the wire from the sender, put a 15 ohms resistor in line and grind that the gauge doesn’t move. It should read high temperature. I am just asking what I might be missing.
     
  4. Apr 22, 2022
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    The specs for the sender are in the TSM. You should read the TSM rather than have me do it for you. I recall it's on the order of 20 ohms at mid scale. Like 10-20-100 cold-mid-hot, or 100-20-10. Something like that. You need to read and follow the TSM.

    http://earlycj5.com/xf_cj5/index.php?threads/143458/
     
    dnb5853, Ol Fogie and Walt Couch like this.
  5. Apr 22, 2022
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    If you ground the sender wire the needle should move. Won't hurt the gauge to ground the sender connection for a moment or so. You can measure continuity between the case and the terminals. It should test open for the temperature gauge.

    If your temperature gauge were bad, I would expect it to read open on a multimeter. 230 seems like a reasonable value, though 50 mA through the gauge seems like a lot. V=IR. You can test it on the bench with a 5 or 6 volt supply, like 3 or 4 AA cells in series.
     
  6. Apr 22, 2022
    EDDY ARNOLD

    EDDY ARNOLD Member

    71655
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    I'm also having fits with my temp gauge reading correctly. 71 CJ 5 Runs right at H heat gun shows 170-180. Standard sensor going try another brand. Boiling water with heat gun reads 205. Also my 2nd set of gas/heat gauges. Didn't want cut another hole in my new dash but its next join oil & volt...My original 69 gauges all work fine.
     
  7. Apr 22, 2022
    CJ51973

    CJ51973 Member

    Versailles, KY
    Joined:
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    I have gather this from the manuals, the troubleshooting gauge guide a number of places online, Terry someone wrote it years ago. I mean no offense by asking for set points but I am wanting to be sure someone doesn’t see something I am missing. I really don’t want to give up and add a temperature gauge. But I don’t want to buy anymore poor quality gauges.
     
  8. Apr 22, 2022
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    I don't have a '71 TSM. Ideally you'd want to look in the correct TSM for your year. If you'd look at the link I posted, the values for a '75 are right there.
     
  9. Apr 22, 2022
    EDDY ARNOLD

    EDDY ARNOLD Member

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    AutoMeter has nice 5 gauge set with speedo little over 500.00
     
  10. Apr 22, 2022
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    The sender ranges will be the same from '55 up to the 80's. Per https://cj5jeeppages.wordpress.com/gauges/ your sender is reading *WAY* too high.

    Note that the gauge A-S-I terminal "ohms" readings in the service manuals and troubleshooting guides will be for stock mechanical type Stewart-Warner or King Seely units, not the newer electronic type parts Omix is selling.
     
  11. Apr 23, 2022
    CJ51973

    CJ51973 Member

    Versailles, KY
    Joined:
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    We’ll that explains my weird readings on the new gauges. I’ll dig back in. Either not getting voltage to the gauge or the gauge is bad. I was getting voltage but I’ll check again. Thanks for the advice. I think I’ll start searching for an old gauge cluster that works as eell
     
  12. Apr 23, 2022
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    Repeat- your sender is way out of spec, per the link I provided "cold" should be more like 200 ohms, warm should be about 20.
     
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