Operation CHARM: Car repair manuals for everyone.

Tachometer: Testing and Inspection

INSPECT TACHOMETER ON-VEHICLE
a. Connect a tune-up test tachometer, and start the engine.

NOTE:
- Reversing the connection of the tachometer will damage the transistors and diodes inside.
- When removing or installing the tachometer, be careful not to drop or subject it to heavy shocks.




b. Compare the tester with tachometer indications.
DC 13.5 V 25 °C at (77 °F)