Mechanics

SPEEDOMETER

1996 GMC Jimmy

Electrical problem
1996 GMC Jimmy 6 cyl Four Wheel Drive Automatic 56000 miles

the speedometer quits working once headlamps or parking lamps are on, but it is not effected by daytime running lites. So at nite I set cruise control and it works fine but the speedometer does not move. Once you stop for 5 or 10 minutes it will then work fine for another 10 minutes then hand will remain stationary.
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Campwizard
March 6, 2008.




But the cruise works when the speedo doesnt? The Speed sensor feeds info to the PCM (computer) it in turn gives a signal out to the speedo for how fast you are going. I would look for a loose/poor connection in the back of the instrument cluster. Sounds like it is losing something when the lights come on, which could be an indicator of a bad connection that cant handle any load on it

Tiny
Jack42
Mar 7, 2008.


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