I don’t know why. This happens out of no where! Everything turns on everything works besides the actual speedometer. It’s stuck at 100. We just replaced the distributor cap and it’s spark plugs with its ignition wires. As well as a new battery. Help.
it’s a 2002 Chevrolet Blazer. 2wd and a v6 4.3 of that helps. 4 door.

 

A while ago, I had my speedometer start sticking at certain speeds. I think the stepper motors can go out to cause this. You might try giving it a hit. But the best solution might be to get a replacement gauge cluster from a wrecking yard. That is what I did. If it matters to you, you might be able to have the mileage reset but I just recorded the difference in my notebook where I list my repairs.

 

Could try drilling a small hole thru the window and using a small piece of wire to push the pointer back.

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Not sure that will work as I doubt it was doing 100 when it stuck.

 

I had this happen on several different blazers and s10 trucks. Sometimes when you interrupt the power it makes a gauge go wacky for a bit. Try these two things:
turn the ignition on and off several times for up to sixty seconds. The repeated jolt to the gauge will sometimes reset it. Or try knocking on it several times, as you would a door. These methods have been successful for me in many instances. Good luck.