99 iO 1.8 speedo just died

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MattiO
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Hi all!

Our speedo suddenly failed while driving, then worked for a few seconds, then finally stopped all together.
Has anyone had this problem before, and/or does anyone know what can cause this? The fuses and power to the guage are all OK.

Any thoughts would be appreciated.

Thanks in advance!

fordem
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The gauge is electronic

and driven from a sensor on the transfer case output shaft, possibilities are the sensor, the wiring or the gauge itself - I'm not certain if a failed sensor will set a fault code, but I think it should - does the odometer still come on with the ignition or is that dead too?

If the odometer is dead, I would suspect the gauge or power to it - I know you said it's good but are you checking to the cluster or the gauge itself?

I've had a similar problemon another vehicle - it was intermittent for many months typically failing if the car had been sitting in the sun - the problem there turned out to be the gauge and I repaced it with a used one, swapping the EPROM chip over to maintain calibration and odometer readings.

MattiO
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The Odometer is still displayed

Hi Fordem, the Odometer and trip meters are still showing although they're no longer clicking over. Interestingly, at the.time the Speedo failed, there was a burning rubber smell in the cabin.

Thanks a bunch for the quick reply!

fordem
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Do you ...

Do you have access/know how to use an oscilloscope?

Basically the speedometer requires three things to operate - +12v power, ground and a pulse train that is generated by the sensor in the transfer case - the unit basically "counts" the pulses and displays the results as speed and distance, I can track down which connectors in the harness feed that pulse train and if you have a way to view it, it could help narriw down the problem area.

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