Tachometer: Description and Operation

The tachometer is a cross-coil, air-core gauge. Power for the tachometer is supplied on circuit G5. This circuit is spliced and supplies power to all the gauges. Ground for the tachometer is provided on circuit Z1. This circuit is spliced and supplies ground for the speedometer, engine oil pressure gauge, engine coolant temperature gauge, and the voltmeter.

Tachometer signal input is supplied by the Powertrain Control Module (PCM) on circuit G21 to the tachometer. This circuit connects to cavity 43 of the PCM connector.

The tachometer drive circuitry translates the signal to a varying analog voltage, which changes the tachometer pointer to correspond with engine speed.