Speedometer failure

My 1995 S10 PU has an speedometer that has stopped working. The speedometer was working on and off for several weeks, I was able to get the speedometer working by placing the transmission in park and shutting off the engine.Also, when the speedometer would not work, the interior fan also stopped working.In addition when the speedometer failed to work the automatic transmission would not shift.



Thanks.

When the speedometer and the transmission both fail to function properly, it is usually just a matter of replacing the Vehicle Speed Sensor (VSS). However, that would not explain any connection to the fan problem. There may be bigger electrical issues here, but my prime suspect would be the VSS.