Operation CHARM: Car repair manuals for everyone.

Tachometer: Description and Operation

When the ignition switch is on ON (II) or START (III), battery voltage is supplied through fuse 1 to the gauges in the gauge assembly. The gauge circuit is grounded at G404.

Tachometer
The tachometer driver circuit receives pulses from the Ignition Control Module (ICM) in the distributor assembly (L4 models).The solid-state tachometer then displays these pulses as engine speed. For each 200 pulses per minute from the ignition control module (ICM), the tachometer displays 100 RPM.