Recently I had a deer run into me. It hit on drivers side near front of door, cracked the lens in the mirror. Just what is best way to fix this? I can try to find complete replacement, housing
and all or order replacement lens. Would I have to remove the unit to use replacement or can I just change glass without taking it all apart? Any thought's

 

Glad you are okay and that was all the damage there was
I would replace the mirror assembly and not just the glass
Even though it may be possible, the repaired ones I see do come back apart at some point
A glass shop will disagree and say they can fix it possibly
If they can, let them fix it,
Just beware the glass might fall out on the freeway when you hit a bump
We used to replace just the glass on a few power mirrors and had about a 25 percent success rate