Speedometer and Odometer

An electric speedometer drive is standard equipment on all models. Integrated circuits control the air core speedometer and stepper motor odometer. Lighting is provided by removable bulb and socket assemblies that insert into the back of the instrument cluster.

The speedometer system consists of the instrument cluster, vehicle speed sensor (VSS) calibrator, VSS and related wiring.

The VSS calibrator is a solid-state device that changes the analog output from the VSS to a digital signal containing 4000 pulses per mile (PPM) for the instrument cluster. The VSS calibrator is matched to the final drive and tire size of each vehicle. It must be replaced with the proper VSS calibrator to match that vehicle. If the final drive or tire size is changed for any reason, the VSS calibrator must be changed to match the new final drive or tire size. If not, the signal will not be accurate for proper speedometer/odometer operation. An incorrect VSS calibrator can also affect anti lock brakes, vehicle control module (VCM) and cruise control systems.

The VSS calibrator is an integral part of the VCM and cannot be serviced separately.

The VSS is a permanent magnet signal generator that sends an analog signal proportional to propeller shaft speed to the VSS calibration. The VSS mounts to the transmission tailshaft extension housing on two-wheel drive models, and to the transfer case output shaft housing on all-wheel drive models.