My passenger side rear view mirror started flapping in the wind this past week... Very distracting. So I disassembled and was able to fix it this weekend.
The reason it became loose is that the adhesive that holds the glass and plastic mount together no longer held.
Here are the tools needed… a #25 Torx socket and drive, Permatex Super Glue, and a flat blade screwdriver or small prying tool.
Remove the interior triangle by pulling the bottom of the triangle away from the door first and then lifting upward on the triangle not to break the tab at the top of the triangle (see tab at the top of the triangle in the photo below to understand why you need to lift it upward).
Remove electrical connector by pulling on it.
Use a #25 Torx drive to remove the three bolts holding the mirror housing to the door.
Use a small prying tool to carefully remove the loose glass from the mirror housing. Mine came-out fairly easy since the adhesive was barely holding-on at this point.
Then remove the plastic mount/holding plate by prying and pulling it off the pan/tilt mount. Note the wires for the defrosting pad that are attached to the plastic mount plate.
Clean both the back side of the mirror and the front surface of the plastic mount plate with glass cleaner or other cleaning fluid.
Use a good glass adhesive, (I used Permatex Super Glue), and apply all around the outer edges and a few spots in the center of the back side of the glass.
Attach the plastic mount plate to the back of the glass and clamp together. I used a number of spring clamps to hold the two pieces together. Let dry overnight.
Reassembly was straight forward. Reconnect the defrost pad (brown wire) connections.
Align and carefully press the mirror assembly back onto the pan/tilt mount in the mirror housing.
Reattach the mirror housing to the door starting with the top bolt first, tighten all three bolts.
Reconnect the electrical connector.
Install interior cover/triangle.