Tachometer: Description and Operation

When the ignition is in ON (II) or START (III) battery voltage is supplied through fuse 13 to the gauges in the gauge assembly.

Tachometer
The tachometer driver in the gauge assembly controls the tachometer. With the ignition in ON (II) or START (III) the tachometer driver receives pulses from the Powertrain Control Module (PCM with A/T) or Engine Control Module (ECM with M/T). The PCM or ECM determines the engine speed from the crank-cylinder sensor. The number of pulses per minute is proportional to engine speed. The tachometer driver converts those pulses to movement of the tachometer needle.