Speedometer reads 65mph at actual zero,and then goes past 120mph

Have you changed the tires and wheels? If not check speed sensor on transmission!

I'm pretty sure that there is a video on you tube on how to reset GM speedometers. Give it a shot.

You need the speedo calibrated, if that is not the cause then either the speedo is defective or their is some unlikely problem with the speed sensor.

Sounds like the speedometer is faulty. If the speed sensor were the problem, the odometer would not work correctly, the transmission would not shift correctly, and the check engine light would be on.

Try giving the gauge pod a solid hit with your hand. This may jolt the needle back.

Otherwise,

• remove the gauge pod.
• remove the front clear panel from the pod.
• move the needle back the zero position.
• reassemble.

See if the speedometer now works.


SD

{: ) Something is terribly wrong with your cluster. I doubt if reprogramming can fix that. A scan tool can read the actual values for these gauges. If they dont match, then you may have to replace your cluster. If scan tool reads abnormal too, then the wirings and other modules must be diagnosed first.

does anybody no what the problem might be

You most likely have a bad servo motor inside the cluster which is what actually moves the speedometer needle. Similar servos also move the rest of the needles in the other gauges. I see this type of failure fairly often and the fix is to remove the cluster and have it sent out for repairs. There are several companies that can do this but I usually take the ones I encounter to my local GM dealer and have them send it out. I prefer to have the one that came out of the vehicle fixed and returned rather than exchanged but either method will work fine. Most places will replace all the servo's and bulbs. Haven't seen one fail again after being repaired. Hope this helps you find your problem!

Check output speed sensor to see if functioning correctly.If working correctly ,suspect an Instrument Panel Control Module or an ECU issue .

It is the cable that connects to the trany..