Speedometer says 70 at idle.
Speedometer, volts, temp gauges don't work properly. on 2003 Chevrolet Silverado 3500
The 03 instrument cluster had problems, send it in to be rebuilt or purchase another, the only fix.
we send our clusters out to AER in La Habra Ca. to be repaired. did you try the gage function reset in the Tech 2 scanner
These 03-06 Silverados are bad about this kind of problem, it's usually caused by failing stepper motors inside the instrument cluster.
Each gauge has a motor that controls it's needle movement and when the motor goes out the gauge will either stick, jump around or die all together.
Another common problem is when all the gauges just stop working all at once (but the back lights inside the instrument cluster still work). This problem is also a problem with the instrument cluster that requires it to be taken out, opened up and repaired.
If you'd like to learn more about the problem and how to get it fixed please visit our site at www.drspeedometer.com
Common problem with these 2003 and some 2004 instrument clusters. They can be repaired - it is not a fault of any other part of the vehicle. For repair of these clusters go here: http://www.mrwhizard.com