Today the tach stopped working on my parents 99Z. My step mom was driving on the freeway and it just dropped to 0. Everything ran and sounded fine. Then just a little bit ago my dad took the car out and the SES light came on and stayed on when he started the car.

Do you know what may be wrong?

 

Take it to have it scanned, i doubt the problems are related it was probably coincidental. You might look at the fuse that powers the gauges, but if it where only the tach it's probably not the fuse.