temperature gauge not working

Discussion in 'Fox 5.0 Mustang Tech' started by 86gtriceeater, Oct 29, 2007.


  1. 86gtriceeater

    86gtriceeater Member

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    temp gauge isnt working...no voltage to the cts sending unit...the gauge itelf has power goint to it....how does one test it besides swapping it out with another one and have done that and cant get either one to work....?
     
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  2. SuperStang83

    SuperStang83 Founding Member

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    Follow the wiring and make sure that everything is hooked up correctly, or get an autometer gauge and know what your temp really is.
     
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  3. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    Check the sending unit wire for continuity. If it's open, the gauge doesnt read.

    If there is too much dope on the threads, it can keep the sender from achieving continuity to ground (it doesnt work or will be inaccurate).

    Good luck.
     
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  4. 86gtriceeater

    86gtriceeater Member

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    how much voltage guys

    how much voltage should be read at the coolant temperature sensor wire? where does that lead go?
     
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  5. bmac50

    bmac50 New Member

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    If by chance your temperature sender F1SZ-10884-A with a build date code prior to 2774 (277th day of 1994) is in your car Ford replaced these .
     

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  6. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    The gauge sender is part of the engine fuel injection harness. The normal location is the driver’s side front of the lower intake manifold.

    The sender wiring routes through the 10 pin salt and pepper shakers. They are known for connection problems.

    Diagram courtesy of Tmoss & Stang&2birds
    [​IMG]

    Diagram of the 10 pin connector wiring
    [​IMG]

    Clean and test the connectors for loose pins and broken/damaged wiring. you can use a jeweler's screwdriver to scrape the pins and to re-shape the pin sockets so that they fit tighter.

    Check the secondary power ground. It is also the ground for the temp sender. The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges. Any car that has a 3G or high output current alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects. The 3G has a 130 amp capacity, so you wire the power side with 4 gauge wire. It stands to reason that the ground side handles just a much current, so it needs to be 4 gauge too.

    Check the resistance of the sender element. It will be greater than 0 but less than 10 megohms.

    If you are adventuresome enough to remove the instrument panel, trace out the wiring to the gauge unit. One side will be 12 volt power and the other side will be the lead to the sender. Measure the resistance between the sender lead on the instrument panel and the wire that plugs onto the top of the gauge sender. It should be less than 2.0 ohms.


    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) or help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

    Ignition switch wiring
    http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

    Fuel, alternator, A/C and ignition wiring
    http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
    http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

    Vacuum diagram 89-93 Mustangs
    http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

    HVAC vacuum diagram
    http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

    TFI module differences & pinout
    http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif
     
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  7. baldy1

    baldy1 New Member

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    Easy way to check the guage and wire is to disconnect the wire from the sending unit and ground it. The guage should peg out. If it doesnt than its either electrical or the guage is bad
     
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