Since this topic comes up every few months
Cause:
* Dry or worn solider of chip within the instrument cluster
Symptoms (can be periodic):
* Speedometer stops functioning
* Rev-counter stops functioning
* Odometer does not display anything
Models: ST215 Caldina
Fix:
1) Remove instrument cluster from dash
2) Remove and open up odometer display within cluster:
3) Locate chip and solder back on:
4) Reassemble
Easy as.