Speedometer Head: Description and Operation

When the ignition switch is on ON (II) or START (III), battery voltage is supplied through fuse 13 to the gauges in the gauge assembly. The gauge circuit is grounded at G4O1.

The odometer and speedometer drive circuits receive pulses from the vehicle speed sensor (VSS). The pulse rate increases as the car accelerates. The frequency and duration of these input pulses are measured and displayed by the speedometer, odometer, and tripmeter.