Saturn ION Forum : “How do I install a passenger side power mirror on the Saturn Ion 3 Quad Coupe?”

You will need to remove either the entire door trim panel, or just the part behind the mirror, if it is removable by itself.  Then, you should find three nuts on three bolts which are part of the mirror assembly, and a wiring harness.  Disconnect the harness, remove the three nuts, replace the mirror, and reverse directions to reassemble.