88/91 caravan side mirror replacement

I am trying to replace JUST THE MIRROR on the driver's side, and was wondering how to go about taking the mirror out of the harness without breaking it worse. (I have an 88 caravan that has the broken mirror and a 91 caravan that is donating the good mirror.) I can get the plastic endcap off, but am unsure how to proceed. I also would like to not remove the whole assembly off the door, if possible.

ANY help or insight will be greatly appreciated! Thanks, :-)