I just purchased a 99
What is the blinking red light on the center front of the dashboard for , it seems to blink when the car is locked ?
Also the rearview mirror has a button onthe bottom that looks like a light (square clear plastic )

 

It indicates that the factory security sytem is active.

I haven't seen that; usually the auto-dimming mirrors have asensor window (about 1/8" by 1/4") toward the bottom-center of the actual reflective part.