It's been a while since I've done it, but you can tilt the mirror all the way to one side and see the clip that keeps the mirror head on. Once you release the clip, the mirror comes out, you unplug wiring and replace the mirror. You can either buy the full mirror/backing plate assembly from Mopar, or get glass only (w/heat grid) at a glass shop as I did. It was about $20.
Pages 23-42 to 23-44 in the 03 service manual detail the replacement.