SPEEDOMETER & RPM GAUGE NOT WORKING WHAT COULD IT BE
SPEED on 2004 Isuzu Ascender
The instrument cluster needs repair. Visit http://www.mrwhizard.com for repair of these clusters
A proper diagnostic check will prove benficial. More than likely, it will be an electrical issue with the gauge cluster.
I'm not a mechanic, but I had a problem like this in my 1998 Chevy Venture van. My mechanic spent about 30 minutes looking into the problem and then found that hitting the dashboard was a true actual fix for the problem. I then saw the same problem listed in our newspapers auto help section and they said to hit the dash with a firm hit to unstick it.
It is probably the Panel Cluster going out. I bought my 2003 Ascender new, and four years later the gauges started going out one at a time now none of them work. I was told it is $600+ to replace it.