92 Olds 98 Regencey Elite driver side mirror

[wtpine]

Just bought car and trying to get into shape. The mirror glass on the driver door has darkened do I need to buy the whole unit or can just the glass be replaced? How do I find what the part number would be? The inside of car is in perfect condition except for the buttons on steering wheel are taped on they do work. There is a bearing sound noise under the hood a friend said it was the air conditioner clutch is this an easy fix?