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Can anyone tell me what the tach pulse is for a 04 VRSCB in order to use with an Auto Meter shift light?
The VRSC ECMs send a tach pulse signal on pin #3 up to model year 2011. This signal is a 12 V square wave once per revolution. IOW, a frequency meter will measure 16.66667 Hz @ 1000 RPM on this pin. This pin was only used on the VRSCSE and VRSCSE2 models in '05 and '06. To use this signal you'll need to take the ECM connector apart and install a wire terminal (and wire). The service manuals explain how to service this Packard 100W connector. The wire terminal is a Delphi Micro-Pack female terminal, P/N 12084912 for 18g wires or P/N 12084913 for 20g to 22g. The HD P/N for a 18g terminal is 72076-00.

In 2012 when the heated O2 sensors were first introduced, the ECMs were changed and pin #3 became a ground for the O2 sensor heaters and the tach signal was no longer available.
 

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Discussion Starter · #3 ·
Thanks for the info, I had mine set to 1.5 pulses, explains why I bounced off the rev limiter before my shift light came on!
 
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