Was your fob working properly after you changed the mirror? Everything working ok since the mirror change and then it just quit recently?
If "yes", I'd suspect the fob. Same thing happened to me with my '97.
All working good and then, one day, the fob wouldn't do anything. New batteries, checked for the infrared signal, solder traces, dirt, etc., all good and still nothing. I was fortunate to get 2 fobs with the car and the spare worked fine. That's when I ordered the new one. Smooth sailing since.