Do you mean the mirror housing or the mirror glass??99 STS Drivers mirror is loose I need to get the trim off to get to the mirror to tighten it.
Exactly what is starting to crack? Sounds like you could be talking about removing the door panel interior trim, but it's not clear what "it" is.....I have tried to pop it out but its starting to crack.
NO speaker on mineYou don't need to remove the trim to tighten the mirror. I had your same problem. I popped of the little tweeter speaker on the trim and through that hole I was able to tighten the mirror with a long combination wrench. I haven't had any issues since.