My speed odometer started at zero today. When I accelerated it went up but would not come down when I stopped. I got up to 40mph, then each time I accelerated it moved higher and higher til it maxxed out at 120mph.
I never got over 50mph. Now its stuck at 120mph. Could it be frozen? Could I have crimped it on some snow/ice? All other gauges are working fine. 2004 LB7.....Its been freezing for a couple of weeks in Pa. (ice storm)
Where does the cable run to? Maybe I can warm it up or something

My speed odometer started at zero today. When I accelerated it went up but would not come down when I stopped. I got up to 40mph, then each time I accelerated it moved higher and higher til it maxxed out at 120mph.
I never got over 50mph. Now its stuck at 120mph. Could it be frozen? Could I have crimped it on some snow/ice? All other gauges are working fine. 2004 LB7.....Its been freezing for a couple of weeks in Pa. (ice storm)
Where does the cable run to? Maybe I can warm it up or something
Quite a common problem in GM products since 99. There is no cable, all electonic. The little motor that runs that guage and there are several others just like it, break their little driveshaft. Scroll down and there are many posts about the same problem. If it's still under warranty, have the dealer fix it, but if not send it out to an outside vendor or if you feel lucky, you can find the motors on EBay. Here's what I did when mine broke. 5 day service from Washington State to Connecticut, repaired and returned. I had all the motors replaced for $170 with 1 year warranty. Takes maybe 10 minutes to remove the cluster and only need a 7mm socket.

http://cgi.ebay.com/03-04-SILVERADO-INSTRUMENT-PANEL-CLUSTER-REPAIR-SERVICE_W0QQitemZ330060367358QQihZ014QQcategoryZ47 121QQcmdZViewItem