After a few times moving the mirror manually, it jammed and couldn't be moved at all. (This meant I couldn't close either mirror, and I have to close the passenger side to park tight to a fence.) Took it apart. Decided to troubleshoot it a bit more. Guessed that the motor was spinning the wrong direction. Switched the motor wires and whadayaknow I could get things to move correctly so long as I didn't screw the outer housing completely down. Realized I didn't grease absolutely everything, so slathered the motor base and plastic housing inside and out. Though it's no longer "manual" in the way it was before (completely unassisted by the motor), I still need to help it - the replacement motor definitely doesn't have enough torque, and there is slop in there that suggests tolerances are nowhere near where they need to be - but at least it closes now.