The tach gets its signal from the ignition trailing coil pack.  If everything else in the instrument cluster works except for the tach, this is a sure sign that there's a problem with the trailing coil pack or it's wiring.  Confirm that the trailings coils are firing first.  Most of the time, it's the trailing coils that's the problem.  A new replacement trailing ignitor is big bucks from the Mazda dealer.  Luckily, good, used units are economical and easy to find.

Questions?  Comments?  Send mail to: