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Marv_Hoag's avatar
Marv_Hoag
Explorer
Sep 29, 2014

Speedometer problems

Having problems with the speedometer readings. Two things are happening. Either it reads perfectly, or reads 10% high. Both are intermittent. Just took a short trip. Going it read correctly, returning it read 10% fast. I was told by Allison repair person the sensor usually works, or it doesn't. The calibration issues is probably not the sensor. Wondering if the problem is in the instrument panel as a grounding problem, or.....?
Class A

3 Replies

  • Dog_Trainer's avatar
    Dog_Trainer
    Explorer
    Sep 29, 2014
    One of the most prominent problems in this issue is ground. I pulled my hair (what little there is) out trying to fix an intermittent speedometer problem.
    I finally replaced the speedometer with a GPS speedometer.
  • Mandalay_Parr's avatar
    Mandalay_Parr
    Explorer
    Sep 29, 2014
    The sensor (which is probably an Encoder or Pulse Generator if you prefer) would likely go into a board. Either of which could be miscounting.

    By all means check the wiring and connections first.
  • DSDP_Don's avatar
    DSDP_Don
    Explorer
    Sep 29, 2014
    Marv....as a cheap fix, I would disconnect the wiring at the sensor and reinstall and check the wiring and grounds at the gauge. It's a bit of a chore to pull the dash, but then you could make sure everything is tight. There are many wires on the back of the dash that are all nutted on. Give them a good snugging up.

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