Trailblazer Speedometer

[Bullethole]

I had posted back in the spring about my speedo being erratic. Not setting back to zero and then showing 75 @ 55 etc. I was advised to swap out the cluster. Now it only shows up infrequently. Today I have another piece of the puzzle solved. It will only have this problem after coming off a highway run where I have used the cruise control. One of the repair sites advised that that this is not a cluster problem but something else relating to the cruise or computer. Any idea what it could be?

[01silverado2500]

I have somewhat of the same problem on my 03 Bravada. It happened once, I started the vehicle up and as soon as i hit my memory seat button my speedo and tach started going crazy. The needles were bouncing around from about 10mph to 70mph and the tach was jmping too all while the vehicle was ideling normaly and not moving. I shut it off and restarted it, everything was fine then.

[GM-Tech]

If the needle doesn't go back to zero when you shut the key off, it can only be a mechanical problem in the stepper motor that drives the needle. There's nothing electrically active that could keep it above zero.