Speedometer not working

Discussion in 'Trucks [ Eighteen Wheelers ]' started by 7seriestv, Mar 30, 2020.

  1. 7seriestv

    7seriestv Light Load Member

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    2005 freightliner century
    Eaton fuller 10 speed smartshift transmission
    Just purchase this truck, been on the road about a month now with it. Some days the speedometer meter work some days it don't. Like wise somedays the qualcom show I'm driving somedays I'm driving and it just show I'm off duty. The miles on the truck increasing and the tachometer work. So far I replace both speed sensors at the back of the transmission, wire harness from tcm to all sensors on the transmission including speed sensor, did continuity test on speed sensor harness going from the speed sensor to the ecm. What else would cause the speedometer and the qualcom to not show that I'm driving.
     
  2. truckdriver31

    truckdriver31 Road Train Member

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    have you tried hitting the dash or gauge first. i got a 2nd ram and if it sits for a few days i got to hit top dash to make speedo work
     
  3. Dino soar

    Dino soar Road Train Member

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    Ahhh...
    The Fonzie technique!

    Now if you can snap your fingers and chicks come running...
     
  4. truckdriver31

    truckdriver31 Road Train Member

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    0AC25845-B6DF-4950-A458-2405C63FF6E2.jpeg
     
  5. 7seriestv

    7seriestv Light Load Member

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    I will try that, at least if it work I have a starting point. Right now I'm out of ideas where to start searching. I was thinking the gauge bad but the qualcom doing the same thing so the problem is somewhere the two tied together
     
  6. truckdriver31

    truckdriver31 Road Train Member

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    maybe speedo sensor
     
  7. 7seriestv

    7seriestv Light Load Member

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    I replace both speed sensors
     
  8. Judge

    Judge Road Train Member

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    The most common causes of a speedometer that stopped working include are a faulty speed sensor, broken gear on the speedometer, damaged wiring, or a faulty engine control unit.

    Have had cable come loose on transmission at the speed sensor.
     
  9. 7seriestv

    7seriestv Light Load Member

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  10. Rideandrepair

    Rideandrepair Road Train Member

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    That explains all the cracked dashboards, Lol