The speedometer sensor relates back to or through the ECM and to the cluster in digital or analog out put.
Check VSS(vehicle speed sensor)on tranny,the most common problem of speedometer errs,providing your vehicle is equipped with a speedometer cable.Also,VSS,will cause erratic speedometer reads. - Big Daddy
If the speedometer and odometer doesn't work I would suspect the VSS (Vehicle Speed Sensor) is faulty.If the speedometer doesn't work but the odometer does, I would suspect the gauge cluster is at fault.
Vehicle Speed Sensor
The speedometer.
Most common would be speedometer cable has broken Remove speedometer head and move vehicle to see if cable moves- if not probably broken - if it does probably problem with speedometer head
If both the speedometer and the odometer do not work I would suspect the VSS (Vehicle Speed Sensor) located on the tail shaft of the transmission is at fault. If only the speedometer doesn't work it's probably a problem with the dash cluster.
getting speedometer to work on a 91 chev it is most likely the vehicle speed sensor on transaxle pass. side, about 40 dollars at part store
Probably a bad vehicle speed sensor.
A faulty vss (vehicle speed sensor).
check the Vehicle Speed Sensor on the transmission or possibly the rear axle.
The VSS vehicle speed sensor on top of the transmission is faulty.
The speedometer needs to work in a vehicle for safety and informative reasons. The causes of it intermittently working could be the lack of electricity, or a problem with the sensor.Ê