Many alternators that I have experience have a terminal marked "W" on them, which is a pulse signal for the tach.
You should ensure your alternator is actually charging, because a symptom of no tach signal is a bad alternator.
It might just be the wiring harness or gauge though...
Originally Posted by Bus dad
ok i talked to BB they said check wire off alt can anyone send me a pic whatcwire thatvwld be