GM Service Manual Online
For 1990-2009 cars only

Object Number: 386790  Size: SH

The reed tachometer consists of two rows of reeds arranged side-by-side. Each reed vibrates when excited by a specific frequency. The reeds are tuned to vibrate at increasing frequencies from left to right. This allows for a visual display of the frequency range from 10-80 Hz.

Due to increasing costs, limited availability and limited diagnostic capability, the reed tachometer is no longer recommended as the primary tool in diagnosing vibration.