'99 Volvo VNL Speedometer Issue

Discussion in 'Volvo Forum' started by Ilya, Aug 5, 2019.

  1. Ilya

    Ilya Bobtail Member

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    Feb 1, 2016
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    Good morning,

    Speedometer is not working on my 1999 Volvo VNL (12.7 Detroit and 13 Spd Transmission). Cluster self test moves both Tach and Speedo needles as supposed to. The engine brake works well, cruise control only works while standing still and raises the engine RPM just above 1,000 (approximately). I have replaced the speed sensor (on the back of the transmission) with a new one bought at the freightliner, for which I had to switch the connector.

    Engine codes:
    MID 136 SID 254 FMI 8
    MID 128 PID 110 FMI 0
    MID 128 PID 84 FMI 12
    MID 128 SID 253 FMI 2
    MID 128 SID 253 FMI 12

    Thank you for help in advance!
     
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  3. blairandgretchen

    blairandgretchen Road Train Member

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    Is it just the speedometer not working, or tachometer as well?

    As I understand tach works off flywheel sensor ( on bell housing), and speedo off the tail shaft sensor on gearbox.

    Did you check resistance of sensor, and check same resistance to wires in back of speedometer cluster (continuity of signal/ broken wire is where I’m going with this) ?
     
    HopeOverMope Thanks this.
  4. Ilya

    Ilya Bobtail Member

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    The tachometer works well - its just the speedometer that does not work.
     
    blairandgretchen Thanks this.
  5. Ilya

    Ilya Bobtail Member

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    I have not checked the resistance of the sensor vs resistance of the panel wire yet.
     
    blairandgretchen Thanks this.
  6. blairandgretchen

    blairandgretchen Road Train Member

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    Try it and see. Worst case is running a jumper set of wires to dash to test.

    I understand those clusters are expensive.

    Rely on GPS or scan guage speed for now?
     
    Guf Thanks this.
  7. Ilya

    Ilya Bobtail Member

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    I have definitely been using GPS to monitor speed,. The biggest issue is the cruise control not working - gets old very quickly.
     
    blairandgretchen Thanks this.
  8. blairandgretchen

    blairandgretchen Road Train Member

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    Check your speed sensor install setting - I know the tach required ‘screw all the way in, then 1.5 turns back, set lock nut ‘

    Just in case it’s too far away.
     
  9. blairandgretchen

    blairandgretchen Road Train Member

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    The cruise can be upset by other things - faulty clutch pedal switch, TPS, etc.

    If it sets at idle and raises RPM, I’d suspect clutch or brake switch - both will disengage cruise.

    Wait - no - isn’t there a park brake switch involved too?
     
    Last edited: Aug 5, 2019
    Reason for edit: second guessing.
    Guf Thanks this.
  10. blairandgretchen

    blairandgretchen Road Train Member

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    I’m no mechanic by the way, just had similar issues in an older truck with 12.7 and N-14.

    Make sure you post your resolution on here to help others, that’s how this forum works.
     
  11. Ilya

    Ilya Bobtail Member

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    Absolutely - I will post a solution once I find out whats wrong.
     
    blairandgretchen Thanks this.
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