2002 F250 7.3L dash gremlins

Discussion in '99+ 7.3L PowerStroke Engine & Drivetrain' started by Dean Levi, Mar 22, 2021.

  1. Dean Levi

    Dean Levi SDD Junior Member

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    Over the past year or so I have a bizarre intermittent problem with the speedometer, tachometer, and warning lights on my 2002 F250. While I am driving and without any warning the needles on both the speedo and tach will slam to full scale, then slam back to zero, then wave around like crazy. A handful of dashboard warning lights flash on and off while it is doing this. The truck continues to run fine while this is happening. I have noticed that if I roll the window up or down it jerks in synch with the speedo and tach needles. I have an aftermarket backup camera installed. The display for the camera turns on and off when the truck is doing the gremlin thing.

    When it first started the gremlin would only happen occasionally. Now it happens almost all the time. I know my batteries are pretty weak, so I plan to replace those to see if that helps.

    Has anyone on this forum ever heard of this kind of thing happening? Does anyone have any ideas on what could cause this? Is it a normal part of the startup sequence for the speedo and tach needles to go full scale and back before the truck starts? I'm wondering if it could be a short in the ignition switch.

    Thanks!
     
  2. Dean Levi

    Dean Levi SDD Junior Member

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    I should note that I recently replaced the alternator - with no effect. I suspected the voltage regulator - which is located inside the alternator.
     
  3. bcvickers

    bcvickers SDD Junior Member

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    Replace or add ground cables from the cab to the frame, cab to the engine, and frame to engine.
     

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