Gauges reading wrong

Discussion in '2005+ Ford Mustang v6 4.0L Tech' started by Captain Al, Aug 2, 2022.

  1. Captain Al

    Captain Al Junior Member

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    Hi everyone, new to forum. My 2005's gauges started going out one-by-one: First the tach was intermittent, then not at all, needle is BELOW zero. since then, the oil pressure gauge, then battery voltage gauge, and most recently, fuel gauge not reading correctly. The only gauge working correctly right now is the temp gauge. All other accessories are working well. I suspect it could be a faulty ground but if any of you know of a fix, please let me know. Thanks
     
  2. Dino Dino Bambino

    Dino Dino Bambino I have a red car

    Age:
    59
    3,397
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    It's more than likely that the gauge stepper motors have died. It's a known problem on the earlier S197s, and the solution is to replace them with the updated x27 stepper motors that you can find in eBay. This is a job you can DIY if you have decent desoldering/soldering skills. Otherwise you can pay ~$130 to these guys to have the repair job done:

    https://circuitboardmedics.com/mustang-instrument-cluster-repair/
     
    crjackson and Joe combs like this.
  3. DieHarder

    DieHarder Senior Member

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    470
    There are grounds you can check (loosen/retighten) see below. Additionally, you may want to look at the electrical circuits for the gauge cluster to see what they have in common for sense lines, power/grounds/SJB (see links). If you notice corrosion on anything you might try cleaning and use some dielectric grease to see if that changes your symptoms or not. If not, it could be the stepper motors as Dino says though I find it odd to see all of them fail one after another so I tend to look at what is electrically common to all/most of them such as grounds or the SJB.

    **Fastest troubleshooting step would be to swap out the cluster with a known good one.** There are a few on feebay and/or you could send yours in for repair.

    To remove the SJB - once out check for water intrusion:

    Electrical Manual - https://iihs.net/fsm/?d=40&f=Instrument Cluster.pdf&p=3
    Instrument Cluster Diagnosis/Testing - https://iihs.net/fsm/?d=343&f=Instrument Cluster.pdf
    Grounds - Instrument cluster/SJB - https://iihs.net/fsm/?d=40&f=Grounds.pdf&p=3
    Power Train/Emissions - Cylinder Head Temp (CHT) - DL - https://iihs.net/fsm/?d=23
     
  4. Captain Al

    Captain Al Junior Member

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    Thanks Everyone. I will tear into the gauge cluster when I get some new stepper motors. After reading some related topics on this forum, I watched a You-Tube video and I think I can handle the task myself. Our 2005 V-6 has been ultra-reliable other than the gauges and with custom wheels and a hood,roof,& trunk dual stripe application, we get tons of compliments everywhere we go!
     
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